\ 



LIBRARY OF CONGRESS. 






UNITED STATES OF AMERICA. 



/ 

August. 



/ V • 



GENERAL 



MEDICAL CHEMISTRY 



FOR THE USE OF 



PRACTITIONERS OF MEDICINE 



V 

^ 



/ 

■y ' 



BY 



R. A. WITTHAUS, AM., M.D., 

Professor of Chemistry and Toxicology in the Medical Department of the University of Vermont ; Pro- 
fessor of Physiological Chemistry in the Medical Department of the University of the City of 
New York ; Member of the Chemical Societies of Paris and Berlin ; Fellow of the New 
York Academy of Medicine and of the American Academy of Medicine, etc. 



"' 




NEW YORK 

WILLIAM WOOD & COMPANY 

27 Great Jones Street 

1881 



Copyright 
WILLIAM WOOD & COMPANY 

1881 



Trow's 

Printing and Bookbinding Company 

201-213 East \itk Street 

New Yokk 



PREFACE. 



Ik the arrangement of this work, it has been deemed advisable to 
depart, in certain points, from the methods usually followed in chemi- 
cal text-books. Those portions treating of technical processes have 
been condensed to a minimum, while the bearings of chemistry upon 
physiology, hygiene, therapeutics, and toxicology, have been treated of 
as fully as the limits of the work have permitted. The division of the 
elements into metals and metalloids has been abandoned as unscientific, 
and a classification has been adopted which the author believes to pos- 
sess advantages over those hitherto followed, especially in that it is 
based upon purely chemical characters. 

Organic chemistry has not been considered as a distinct division of 
the subject, but simply as the chemistry of the compounds of carbon; 
an arrangement not only logical, but sanctioned by the works of Feser, 
Schutzenberger, and others. The classification of the carbon com- 
pounds is based, as far as possible, upon their relations to the different 
series of hydrocarbons. 

The size of the volume being limited, the author has preferred to 
abstain from the use of illustrations, thinking that the space could be 
better utilized as it has been. Through mistake of the printer in 
casting up the copy, he has also been obliged to condense that portion 
of the work treating of the third and fourth classes of elements 
more than he wished, and quite out of proportion to the rest of 
the work. 

It is hardly necessary to state that the modern system of notation 
has been followed. All weights and measures are given in the metric 
system, and temperatures in degrees of the Centigrade scale. 

E. A. W. 

766 Madison Avenue, New York, 
August 7, 1881. 



CONTENTS. 



INTRODUCTION. 

PAGE 

General properties of matter 2 

Elements and compounds 7 

Laws governing the combination of elements 7 

The atomic theory 8 

Atomic and molecular weights 11 

Symbols, formulae, equations , 16 

Radicals, acids, bases, salts 17 

Nomenclature 20 

Oxides, hydrates, and chlorides 23 

Typical f ormulas and formulae of constitution 23 

Classification of elements 26 

Physical characters of chemical interest 28 



SPECIAL CHEMISTRY. 

Elements of Class 1 33 

Hydrogen 33 

Oxygen 35 

Ozone .... 37 

Water 



r>-» 



Elements of Class II 09 

Chlorine Group 69 

Fluorine 69 

Chlorine 70 

Bromine 77 

Iodine 78 



VI CONTENTS. 

PAGK 

Sulphur Group 82 

Sulphur , 82 

Selenium and tellurium 93 

Nitrogen Group <, 94 

Nitrogen 94 

Air i 95 

Phosphorus 106 

Arsenic f , 116 

Antimony 131 

Boron Group 139 

Boron 139 

Carbon Group. 141 

Carbon 141 

Classification of carbon compounds 148 

First series of hydrocarbons 157 

Second series of hydrocarbons 227 

Third series of hydrocarbons 287 

Fourth series of hydrocarbons 292 

Fifth series of hydrocarbons 315 

Sixth series of hydrocarbons 334 

Seventh series of hydrocarbons 336 

Eighth series of hydrocarbons 336 

Ninth series of hydrocarbons 337 

Tenth series of hydrocarbons 337 

Eleventh series of hydrocarbons 337 

Higher series of hydrocarbons 338 

Cyanogen compounds 342 

Glucosides 342 

Alkaloids 346 

Albuminoids 360 

Animal ferments 368 

Animal coloring matters 369 

Silicon 372 

Molybdenum Group 373 

Elements of Claso III 374 

Gold Group 374 

Iron Group 374 

Chromium 375 

Manganese 376 

Iron 377 

Aluminium Group 381 

Aluminium 381 



CONTENTS. Vll 

PAGE 

Lead Group 384 

Lead 384 

Bismuth Group 388 

Bismuth 388 

Tin Group 390 

Tin 390 

Platinum and Rhodium Groups— 392 

Platinum 392 

Elements of Class IV 393 

Sodium Group 393 

Lithium 393 

Sodium 394 

Potassium 399 

Silver 407 

Ammonium 408 

Calcium Group 411 

Calcium 411 

Barium ♦ 415 

Magnesium Group 416 

Magnesium 416 

Zinc 418 

Nickel Group 419 

Nickel 419 

Cobalt 419 

Copper Group 420 

Copper 420 

Mercury 423 



GENERAL 



MEDICAL CHEMISTRY. 



Part 1. 

INTRODUCTION. 



It is difficult to give at the outset a clear and concise idea of what 
is understood as chemical science. The best and simplest definition of 
chemistry is a modification of that given by Webster: That branch of 
science which treats of the composition of substances, their changes in 
composition, and the laws governing such changes. It will be seen that 
the essential character of the science is that it has to deal with comjiosi- 
tion, and in this the line between physical and chemical phenomena is more 
sharply drawn than that between the individual varieties of the former. 

A bar of soft iron is the same in composition, whether it be hot or 
cold, luminous or non-luminous, magnetized or not magnetized. When, 
however, it comes under the dominion of chemical action, its composition 
is changed, and, although the resulting substance contains iron, it differs 
in its appearance and properties from that metal. Moreover, this change 
in composition, once brought about, is permanent until another change 
is Avrought by another manifestation of chemical action; on the other 
hand, the peculiar property communicated to a substance by a physical 
force is temporary, and only manifested during the action of that force. 

However distinct chemical may thus be from physical forces, it is 
none the less united with them in that grand correlation whose existence 
was first announced by Grove, in 1842. As, from chemical action, mani- 
festations of every variety of physical force may be obtained: light, heat 
and mechanical force from the oxidation of carbon; and electrical force 
from the action of zinc upon sulphuric acid — so does chemical action have 
its origin, in many instances, in the physical forces. Luminous rays bring 
about the chemical decomposition of the salts of silver, and the chemical 
union of chlorine and hydrogen; by electrical action a decomposition of 
many compounds into their constituents is instituted, while instances are 
abundant of reactions, combinations, and decompositions which require a 
certain elevation of temperature for their production. While, therefor, 



2 GENERAL MEDICAL CHEMISTRY. 

chemistry in the strictest sense of the term deals only with those actions 
which are attended by a change of composition in the material acted 
upon, yet chemical actions are so frequently, nay universally, affected by 
existing physical conditions, that the chemist is obliged to give his at- 
tention to the science of physics, in so far, at least, as it has a bearing 
upon chemical reactions, to chemical physics — a branch of the subject 
which has afforded very important evidence in the support of theoretical 
views originating from purely chemical reactions. 



General Properties of Matter. 

Indestructibility. — The result of chemical action is change in the 
composition of the substance acted upon, a change accompanied by cor- 
responding alterations in its properties. Although we may cause matter 
to assume a variety of different forms and render it, for the time being, 
invisible, yet in none of these changes is there the smallest particle of 
matter destroyed. When carbon is burned in an atmosphere of oxygen, 
it disappears, and, so far as we can learn by the senses of sight or touch, 
is lost; but the result of the burning is an invisible gas, whose weight is 
equal to that of the carbon which has disappeared, plus the weight of the 
oxygen required to burn it. 

Weight. — All bodies attract each other with a force which is in direct 
proportion to the amount of matter which they contain. The force of 
this attraction exerted upon surrounding bodies by the earth becomes 
sensible as weight, when the motion of the attracted body toward the 
centre of gravity of the earth is prevented. 

In chemical operations we have to deal with three kinds of weight : 
apparent, absolute, and specific. 

The apparent weight, or relative weight, of a body is that which we 
usually determine with our balances, and is, if the volume of the body 
weighed be greater than that of the counterpoising weights, less than 
its true weight. Every substance placed in a liquid or gaseous medium 
suffers a loss of apparent weight equal to that of the volume of the medium 
so displaced, and is buoyed up to that extent. A cork placed in water 
sinks until it has displaced a volume of water whose weight is equal to 
its own. For this reason the apparent weight of some substances may be 
a minus quantity; thus, if the air contained in a vessel suspended from one 
arm of a poised balance be replaced by hydrogen, that arm of the balance 
to which the vessel is attached will rise, indicating a diminution in weight. 

The absolute weight of a body is its weight in vacuo. It is only deter- 
mined in very accurate chemical work, by placing the entire weighing ap- 
paratus under the receiver of an air-pump, or, in the case of gases, ap- 
proximately, by first weighing the vessel from which the air has been 
pumped, and afterward filled with the gas. 

By the specific weight, or specific gravity of a substance, is understood 
the weight of a given volume of that substance as compared with the 
weight of an equal volume of some substance taken as a standard of com- 
parison. It is a well-known fact that equal volumes of different sub- 
stances differ from each other in weight; thus, a litre of hydrogen weighs 



GENERAL PROPERTIES OF MATTER. 3 

0.0896 grams, while the same volume of platinum weighs 21.500 grams, 
or about 200,000 times as much. 

The substance taken as the unit of the specific gravities of solids and 
liquids is water. The specific weights of gases are usually referred to air 
as a unit; it is better, however, to adopt hydrogen as such unit (see p. 
15). When we say that the specific gravity of sulphuric acid is 1.8, we 
mean that, volume for volume, sulphuric acid is one and eight-tenths 
times as heavy as water. 

The determination of the specific weight of a substance is frequently 
of great service. Sometimes it affords a rapid means of distinguishing 
between two substances similar in appearance; sometimes in determining 
the quantity of an ingredient in a mixture of two liquids, as alcohol and 
water; and frequently in determining approximately the quantity of 
solid matter in solution in a liquid; it is the last object which we have 
in view in determining the specific gravity of the urine. 

An aqueous solution of a solid has a higher specific gravity than pure 
water, the increase in specific gravity following a regular but different 
rate of increase with each solid. In a simple solution — one of common salt 
in water, for instance — the proportion of solid in solution can be deter- 
mined from the specific gravity. In complex solutions, such as the urine, 
the specific gravity does not indicate the proportion of solid in solution 
with accuracy. In the absence of sugar and albumen, a determination of 
the specific gravity of urine affords an indication of the amount of solids 
sufficiently accurate for usual clinical purposes. Moreover, as urea is 
much in excess over other urinary solids, the oscillations in the specific 
gravity of the urine, if the quantity passed in twenty-four hours be con- 
sidered, and in the absence of albumen and sugar, indicate the variations 
in the elimination of urea, and consequently the activity of disassimilation 
of nitrogenous material. 

To determine the specific gravity of substances, different methods arc 
adopted, according as the substance is in the solid, liquid, or gaseous 
state ; is in mass or in powder; or is soluble or insoluble in water. 

Solids. — First. The substance is heavier than water, insoluble in that 
liquid, and not in powder. It is attached by a fine silk fibre to a hook 
suitably situated on one arm of the balance, and weighed. A beaker full 
of pure water is so arranged that the substance, still attached to the 
balance, is immersed in the liquid; in which condition it is again weighed. 
The second weight will be found to be less than the first. By dividing 
the weight in air by the loss in water the specific gravity, water=1.00, is 
obtained. Example: 

A piece of lead weighs in air 82.0 

A piece of lead weighs in water 74.9 

Loss in water 7.1 

82.0 

11.55 = sp. gr. of lead. 



7.1 



If the substance be in fine powder, the specific gravity bottle (see p. 
4) is used. The bottle, filled with water, and the powder, previously 
weighed and in a separate vessel, are weighed together. The water is 



4 GENERAL MEDICAL CHEMISTRY. 

poured out of the bottle, into which the powder is then introduced, with 
enough water to fill the bottle completely. The weight of the bottle and 
its contents is now determined, and is less than the first weight by the 
weight of the volume of water displaced by the powder. Here again the 
specific gravity is obtained by dividing the weight of the powder alone 
by the loss between the first and second weighings. 

Second. — If the substance be lighter than water, a sufficient bulk of 
some heavy substance, whose specific gravity is known, is attached to it 
and the same method followed, the loss of weight of the heavy substance 
being subtracted from the total loss. Example:. >' 

A fragment of wood weighs 24 

A fragment of lead weighs 44 

Wood with lead attached weighs 68 

Wood with lead attached weighs in water. ... 16 

Loss of weight of combination 52 

Loss of weight of lead in water 6 

Loss of weight of wood 46 

24 

* — = 0.5217=:sp. gr. of wood. 

46 

Third. — If the substance be soluble in water, its specific gravity, re- • 
f erred to some liquid in which it is insoluble and whose specific gravity is 
known, is determined by using that liquid as water is used in 1°. From 
this the specific gravity of the solid, referred to water, is determined by 
multiplying the specific gravity so obtained by that of the liquid used. 
Example: 

A piece of potassium weighs 2.576 

A specific gravity bottle full of naphtha, sp. gr. 0.758, 

weighs 22.784 

25.360 
The bottle with potassium and naphtha weighs 23.103 

Loss ..... 2.257 

2.576 



2.257 



1.141 x0.758=0.865=sp. gr. of potassium. 



Liquids. — The specific gravity of liquids is determined by the specific 
gravity bottle, sometimes called picnometer, or by the spindle or hydrom- 
eter. 

First. — The method by the bottle is the more accurate, and, if a bal- 
ance be at hand, easily conducted. A bottle of thin glass is so made as 
to contain exactly a given volume of distilled water at a given tempera- 
ture, say 100 c.c. at 15° C. ; the weight of the bottle is also known once 
for all. To use the picnometer, it is'simply filled with the liquid to be ex- 



GENERAL PROPERTIES OF MATTER. 5 

amined and weighed. The weight obtained, minus that of the bottle, is the 
specific gravity sought if the bottle contain 1000 c.c; y 1 ^ if 100 c.c, etc. 
Example: having a bottle whose weight is 35.35, and which contains 100 
c.c; filled with urine it weighs 137.91, the specific gravity of the urine is 
137.91-35.35 = 102.56x10=1025.6 "Water =1000. 

Second. — The method by the hydrometer is based upon the fact that 
a solid will sink in a liquid until it has displaced a volume of the liquid 
whose weight is equal to its own; and all forms of hydrometers are sim- 
ply contrivances to measure the volume of liquid which they displace when 
immersed. The appearance of the hydrometer most used by physicians, 
the urinometer, is too well known to require description. It should 
not be chosen too small, as the larger the bulb and the thinner and longer 
the stem, the more accurate will be its indications. Owing to prevailing 
carelessness in the manufacture of urinometers and to the impossibility of 
reading the graduations with the same accuracy that can be attained in 
detecting small differences in weight, their indications are never as pre- 
cise as those obtained by the picnometer. 

In all determinations of specific gravity it is of great importance to 
have the liquid examined at the temperature for which the instrument is 
graduated, for the reason that all liquids expand with heat and contract 
when cooled, and consequently the result obtained will be too low if the 
urine or other liquid be at a temperature above that at which the instru- 
ment is intended to be used, and too high if below that temperature. An 
accurate correction may be made for temperature in simple solutions; in 
a complex fluid like the urine, however, this can only be done roughly by 
allowing 1° of specific gravity for each 3° C. (5.4° Fahr.) of variation in 
temperature. 

The determination of the specific gravity of gases and vapors requires 
all the facilities of a well-appointed laboratory, and, although of the 
greatest importance to the chemist (see p. 15), will rarely be attempted 
by the physician. 

States of Matter. — Matter exists in one of three states, solid, liquid, 
and gaseous. In the solid form the particles of matter are comparatively 
close together, and are separated with more difficulty than are those of 
liquid or gaseous matter; or, in other words, the cohesion of solid matter 
is greater than that of the other two forms. In the liquid the particles 
are less firmly bound together and are capable of freer motion about one 
another. In the gas the mutual attraction of the particles disappears 
entirely, and their distance from each other depends upon the pressure to 
which the gas is subjected. 

The term fluid applies to both liquids and gases, the former being 
designated as incompressible, from the very slight degree to which their 
volume can be reduced by pressure. The gases are designated as com- 
pressible fluids t from the fact that their volume can be reduced by pres- 
sure to an extent limited only by their passage into the liquid form. 

It is highly probable that all substances which are not decomposed 
when heated are capable of existing in the three forms of solid, liquid, 
and gas. There are, however, some substances which are only known in 
two forms — as alcohol, or in a single form — as carbon; probably because we 
are as yet unable to produce artificially a temperature sufficiently low to 
solidify the one, or sufficiently high to liquefy or volatilize the other. 

The passage of a substance from one form to another is always at- 
tended by the absorption or liberation of a definite amount of heat. In 
passing from the solid to the gaseous form a body absorbs a definite 



6 GENERAL MEDICAL CHEMISTRY. 

amount of heat with each change of form. If a given quantity of ice at 
a temperature below the freezing-point of water be heated, its tempera- 
ture gradually rises until the thermometer marks 0° C, at which point 
it remains stationary until the last particle of ice has disappeared. At 
that time another rise of the thermometer begins, and continues until 
100° C. is reached (at 760 mm. of barometric pressure), when the water 
boils, and the thermometer remains stationary until the last particle of 
water has been converted into steam; after which, if the application of 
heat be continued, the thermometer again rises. During these two periods 
of stationary thermometer, heat is taken up by the substance, but is not 
indicated by the thermometer or by the sense. Not being sensible, it is 
said to be latent, a term which is liable to mislead, as conveying the idea 
that heat is stored up in the substance as heat/ such is not the case. 
During the period of stationary thermometer the heat is not sensible as 
heat, for the reason that it is being used up in the work required to effect 
that separation of the particles of matter which constitutes its passage 
from solid to liquid or from liquid to gas. The amount of heat required 
to bring about the passage of a given weight of a substance from the 
denser to the rarer form is always the same, and the t emperature indicated 
by the thermometer during this passage is always the same for that sub- 
stance, unless in either case a modification be caused by a variation in 
pressure. The degree of temperature indicated by the thermometer while 
a substance is passing from the solid to the liquid state is called its ^f using- 
point/ that indicated during its passage from the liquid to the gaseous 
form, its boiling-point. 

The absorption of heat by a volatilizing liquid is utilized in the arts 
and in medicine for the production of cold (which is simply the absence of 
heat), in the manufacture of artificial ice and in the production of local 
anaesthesia by the ether-spray. The removal of heat from the body in this 
way, by the evaporation of perspiration from the surface, is an important 
factor in the maintenance of the body temperature at a point consistent 
with life. 

When a substance passes from a rarer to a denser form it gives out — 
liberates — an amount of heat equal to that which it absorbed in its pas- 
sage in the opposite direction. It is for this reason that, while we apply 
heat to convert a liquid into a vapor, we apply cold to reduce a gas to a 
liquid. As a rule, the thermometrical indication is the same in which- 
ever direction the change of form occurs; some substances, however, so- 
lidify at a temperature slightly different from that at which they fuse. 

Most solids, when heated, are first converted into liquids, and these 
into gases; there are, however, some exceptions to this rule. Solids which 
pass directly from the solid to the gaseous form are said to sublime. 

Divisibility. — All substances are capable of being separated, with 
greater or less facility, by mechanical means into minute particles. With 
suitable apparatus, gold may be divided into fragments, visible by the aid 
of the microscope, whose weight would be -g-oo o o o 1 o o o o o o °^ a g ram j anc ^ 
it is probable that when a solid is dissolved in a liquid a still greater sub- 
division is attained. 

Although we have no direct experimental evidence of the existence of 
a limit to this divisibility, we are warranted in believing that matter is not 
infinitely divisible. A strong argument in favor of this view being that, 
after physical subdivision has reached the limit of its power with regard to 
compound substances, these may be further divided into dissimilar bodies 
by chemical means. 



LAWS GOVERNING THE COMBINATION OF ELEMENTS. 7 

The limit of mechanical subdivision is the molecule of the physicist, 
the smallest quantity of matter with which he has to deal. 



Elements and Compounds. 

If we examine the various substances existing upon and in our earth, 
we find that many of them can be so decomposed as to yield two or more 
other substances, distinct in their properties from the substance from 
whose decomposition they resulted, and from each other. If, for ex- 
ample, sugar be treated with sulphuric acid it blackens, and after a 
while a mass of charcoal separates. Upon further examination we find 
that water has also been produced. From this water we may by simple 
means obtain two gases, differing from each other widely in their proper- 
ties. Sugar is therefor made up of carbon and the two gases, hydrogen 
and oxygen; but it has the properties of sugar, and not those of either of 
its constituent parts. Moreover, if we analyze any number of samples of 
pure sugar, we will find all of them to contain the same proportionate 
quantities of carbon, hydrogen, and oxygen (see below). Such a substance 
as sugar is called a compound. 

There exist in nature other substances which it has been impossible, 
hitherto, to decompose into other dissimilar bodies; such as those are 
called simple substances or elements. 

There are sixty -four elements at present known; but it is probable 
that, as our methods of investigation are improved, this number will be in- 
creased by the discovery of other elements, existing only in small quanti- 
ties. Indeed, during the past year or two the discovery of elements not 
included in the above number, scandium, decipium, p>hilippium, and of 
ytterbium, has been announced. 



Laws Governing the Combination of Elements. 

The alchemists, Arabian and European, contented themselves in accu- 
mulating a store of knowledge of isolated phenomena, without, as far as we 
know, attempting, in any serious way, to group them in such a manner as 
to learn the laws governing their occurrence. It was not until the latter 
part of the last century, 1777, that Wenzel, of Dresden, implied, if he did 
not distinctly enunciate, what is known as the law of reciprocal propor- 
tions. A few years later, Richter, of Berlin, confirming the work of 
Wenzel, added to it the law of definite proportions, usually called Dal- 
ton's first law. Finally, as the result of his investigations from 1804 to 
1808, Dalton added the law of multiple proportions, and, reviewing the 
work of his predecessors, enunciated the results clearly and distinctly. 

Considering these laws, not in the order of their discovery, but in that 
of their natural sequence, we have: 

The law of definite proportions, stated in modern language, is that 
the relative weights of elementary substances in a compound are definite 
and invariable. If, for example, we analyze water, we find that it is com- 
posed of eight parts by weight of oxygen for each part by weight of hydro- 
gen, and that this proportion exists in every instance, whatever the source 
of the water. If, instead of decomposing, or analyzing water, we start 
from its elements, and, by synthesis, cause them to unite to form water, we 
find that, if the mixture be made in the proportion of eight oxygen to 



8 GENERAL MEDICAL CHEMISTRY. 

one hydrogen by weight, the entire quantity of each gas will be consumed 
in the formation of water. But if an excess of either have^been added to 
the mixture, that excess will remain after the combination. This is 
true of all chemical compounds, and in this we have one distinction be- 
tween a chemical compound and a mere mixture of two substances; in 
the former the proportion of the constituents is always the same, while 
in the latter it is variable. Another distinction between compounds and 
mixtures is that the former have properties distinct from those of their 
constituents, and that the properties of these only become evident after 
decomposition of the compound; while mixtures possess the properties 
inherent in one or all of their constituents. 

The law of multiple proportions, or Dalton's second law, is that when 
two elements unite with each other to form more than one compound, the 
resulting compounds contain simple multiple proportions of one element 
as compared with a constant quantity of the other. 

Oxygen and nitrogen, for example, unite with each other to form no 
less than five compounds. Upon analysis we find that in these the two 
elements bear to each other the following relations by weight: 

In the first, 14 parts of nitrogen to S of oxygen. 
In the second, 14 parts of nitrogen to 8 x 2 = 16 of oxygen. 
In the third, 14 parts of nitrogen to 8 x 3 = 24 of oxygen. 
In the fourth, 14 parts of nitrogen to 8 x 4=32 of oxygen. 
In the fifth, 14 parts of nitrogen to 8 x 5 = 40 of oxygen. 

Finally, the third law, that of reciprocal proportions, is to the effect 
that the ponderable quantities in which substances unite with the same 
substance express the relation, or a simple multiple thereof, in which they 
unite with each other. Or, as Wenzel stated it, " the weights b, b ', b" of 
several bases which neutralize the same weight a of an acid are the same 
which will neutralize a constant weight a' of another acid ; and the weights 
a, a,' a," of different acids which neutralize the same weight b of a base 
are the same which will neutralize a constant weight of another base b'." 



'o' 



The Atomic Theory. 

The laws of Wenzel, Richter, and Dalton, given above, are simply gen- 
eralized statements of certain groups of facts, and, as such, not only admit 
of no doubt, but are the foundations upon which chemistry as an exact 
science is based. Dalton, seeking an explanation of the reason of being 
of these facts, was led to adopt the view, held by the Greek philosopher 
Democritus, that matter was not infinitely divisible. He retained the 
name atom (arop;s:=indivisible), given by Democritus to the ultimate 
particles of which matter was supposed by him to be composed; but ren- 
dered the idea more precise by ascribing to these atoms real magnitude 
and a definite weight, and by considering elementary substances as made 
up of atoms of the same kind, and compounds as consisting of atoms of 
different kinds. 

This hypothesis, the first step toward the atomic theory as entertained 
to-day, afforded a clear explanation of the numerical results stated in the 
three laws. If hydrogen and oxygen always unite together in the propor- 
tion of one of the former to eight of the latter, it is because, said Dalton, 
the compound consists of an atom of hydrogen, weighing 1, and an atom 



Hydrogen. 


Oxygen. 




25.0 


.... 


= 100 


14.3 


. . . . 


= 100 


• . • • 


57.1 


= 100 


» • • • 


72.7 


= 100 



THE ATOMIC THEORY. 9 

of oxygen, weighing 8. If, again, in the compounds of nitrogen and 

oxygen, we have the two elements uniting in the proportions 14 : 8 

14: 8 x 2 14 : 8 x 3 14 : 8 x 4 14 : 8 x 5, it is because they are 

severally composed of an atom of nitrogen weighing 14, united to 1, 2, 
3, 4 or 5 atoms of oxygen, each weighing 8. Further, that compounds do 
not exist in which any fraction of 8 oxygen enters, because 8 is the 
weight of the indivisible atom of oxygen. 

One of the chief advantages of Dalton's hypothesis is in the intro- 
duction of this precise and simple relation between the quantities of the 
constituents of a compound. Chemists before Dalton's day, in express- 
ing the results of their analyses, did not progress beyond statements of 
the percentage composition. Expressing the composition of four of the 
carbon compounds in percentages, we have: 

Carbon. 

Marsh gas 75.0 

Olefiant gas 85.7 

Carbonic oxide 42.9 

Carbonic acid 27.3 

At first sight, these figures convey nothing beyond the mere centesimal 
composition of the substances which they express. The cardinal point 
of Dalton's discovery lies in his translation of them into the simple rela- 
tions: 

Carbon. Hydrogen. Oxygen. 

Marsh gas 6 2 

Olefiant gas 6 1 

Carbonic oxide 6 . . 8 

Carbonic acid 6 . . 16 

Dalton's hypothesis of the existence of atoms as definite quantities did 
not, however, meet with general acceptance. Davy, Wollaston, and others 
considered the quantities in which Dalton had found the elements to unite 
with each other, as mere 'proportional numbers, or equivalents, as they 
expressed it, nor is it probable that Dalton's views would have received 
any further recognition until such time as they might have been exhumed 
from some musty tome, had their publication not been closely followed 
by that of the results of the labors of Humboldt and of Gay Lussac, con- 
cerning the volumes in which gases unite with each other. 

In the form of what are known as Gay Lussac's laws, these results are: 

First. — TJiere exists a simple relation between the volumes of gases 
which combine with each other. 

Second. — There exists a simple relation between the sum of the volumes 
of the constituent gases , and the volume of the gas formed by their union. 
For example: 

1 volume chlorine unites with 1 volume hydrogen to form 2 volumes 

hydrochloric acid. 
1 volume oxygen unites with 2 volumes hydrogen to form 2 volumes 

vapor of water. 
1 volume nitrosren unites with 3 volumes hvdrogen to form 2 volumes 

ammonia. 



10 GENERAL MEDICAL CHEMISTRY. 

1 volume oxygen unites with 1 volume nitrogen to form 2 volumes 

nitric oxide. 
1 volume oxygen unites with 2 volumes nitrogen to form 2 volumes 

nitrous oxide. 

Berzelius, basing his views upon these results of Gay Lussac, modified 
the hypothesis of Dalton and established a distinction between the equi- 
valents and atoms. The composition of water he expressed, in tr e nota- 
tion which he was then introducing, as being H 2 0, and not HO as Dal- 
ton's hypothesis called for. As, however, Berzelius still considered the 
atom of oxygen as weighing 8, he was obliged also to consider the atoms 
of hvdrogren and of certain other elements as double atoms — a fatal defect 
in his system, which led to its overthrow and the re-establishment of the 
formula HO for water. 

It was reserved to Gerhardt to clearly establish the distinction be- 
tween atom and molecule; to observe the bearing of the discoveries of 
Avogadro and Ampere upon chemical philosophy; and thus to establish 
the atomic theory as entertained at present. 

As a result of his investigations in the domain of organic chemistry, 
Gerhardt found that, if Dalton's equivalents be adhered to, whenever 
carbonic acid or water is liberated by the decomposition of an organic 
substance, it is invariably in double equivalents, never in single ones; 
always 2C0 2 or 2HO or some multiple thereof, never C0 2 or HO. He 
further found that if the equivalents C = 6, H = l, and = 8 be retained, the 
formulae became such that the equivalents of carbon are always divisible 
by two. In fact, he found the same objections to apply to the notation 
then in use, that had been urged against that of Berzelius. 

In 1811, Avogadro, from purely physical researches, had been enabled to 
state the law which is now known by his name, to the effect that equal 
volumes of all gases, under like conditions of temperature and pressure, 
contain equal ?iumbers of molecules. 

In the hands of Gerhardt this law, in connection with those of Gay 
Lussac, became the foundation of what is sometimes called the " new 
chemistry." Bearing in mind Avogadro's law, we may translate the first 
three combinations given in the table on p. 9 into the following: 

1 molecule of chlorine unites with 1 molecule of hydrogen to form 2 

molecules of hydrochloric acid. 
1 molecule of oxygen unites with 2 molecules of hydrogen to form 2 

molecules of vapor of water. 
1 molecule of nitrogen unites with 3 molecules of hydrogen to form 2 

molecules of ammonia. • 

But the ponderable quantities in which these combinations take place 
are: 

35.5 chlorine to 1 hydrogen. 

16 oxygen to 2 hydrogen. 

14 nitrogen to 3 hydrogen. 

And as single molecules of hydrogen, oxygen, and nitrogen are in these 
combinations subdivided to form 2 molecules of hydrochloric acid, water, 
and ammonia, it follows that these molecules must each contain two 
equal quantities of hydrogen, oxygen, and nitrogen, less in size than the 
molecules themselves. And, further, as in these instances each molecule 



ATOMIC AND MOLECULAR WEIGHTS VALENCE. 11 

contains two of these smaller quantities, or atoms, the relation between 
the weights of the molecules must be also the relation between the 
weights of the atoms, and we may therefor express the combinations 
thus: 

1 atom of chlorine weighing ) ., . , j 1 atom of hydrogen weighing 

35.5 j (1; 

1 atom of oxygen weighing ) ., . , , j 2 atoms of hydrogen weighing 

16 j- unites witn ( i ea ch; 

1 atom of nitrogen weighing [ ., . , , j 3 atoms of hydrogen weighing 

14 j- unites witn | i ea ch; 

and consequently, if the atom of hydrogen weighs 1, that of chlorine 
weighs 35.5, that of oxygen 16, and that of nitrogen 14. 



Atomic and Molecular Weights — Valence. 

Atomic weights. — The distinction between molecules and atoms may 
be expressed by the following definitions: 

A molecule is the smallest quantity of any substance that can exist in 
the free state. 

An atom is the smallest quantity of an elementary substance that can 
enter into a chemical reaction. 

The molecule is always made up of atoms, upon whose nature, num- 
ber, and arrangement with regard to each other, the properties of the sub- 
stance depend. In an elementary substance the atoms composing the 
molecules are the same in kind, and usually two in number. In com- 
pound substances they are dissimilar and vary in quantity from two in a 
simple compound, like hydrochloric acid, to several hundreds in the more 
complex organic substances. Obviously, the word atom can only be used 
in speaking of an elementary body, and that only while it is passing 
through a reaction. The term molecule, on the other hand, applies indif- 
ferently to elements and compounds. 

The atoms have, as we have seen, definite relative weights; and upon 
an exact determination of these weights depends the entire science of 
quantitative analytical chemistry. A vast amount of labor has been be- 
stowed upon fixing these quantities accurately. Berzelius, who was the 
first to recognize their importance, devoted over thirty years to the task, 
which he performed so carefully that many of the weights which he gave 
are those still in use. Subsequently, as new elements were discovered, 
and as methods of investigation were improved, other determinations 
were made by Dumas, Marignac, Erdmann, Marchand, Stas, Cooke, and 
others. 

These weights, determined by repeated and careful analyses of per- 
fectly pure compounds of the elements, express the weight of one atom 
of the element as compared with the weight of one atom of hydrogen, 
that being the lightest element known. What the absolute xoeight of an 
atom of any element may be we do not know, nor would the knowledge 
be of any service did we possess it. 

The following table contains a list of the elements at present known, 
with their atomic weights: 



12 



GENERAL MEDICAL CHEMISTRY. 



ELEMENTS. 



Name. 


A. 

Symbol. 


B. 

Atomic 
weight. 


C. 

Specific heat. 


D. 

Atomic 
heat. 
BxC. 


Aluminium 


Al. 

Sb. 

As. 

Ba. 

Bi. 

Bo. 

Br. 

Cd. 

Cs. 

Ca. 

C. 

Ce. 

CI. 

Cr. 

Co. 

Cu. 

D. 

E. 

Fl. 

Ga. 

Gl. 

Au. 

H. 

In. 

I. 

Ir. 

Fe. 

La. 

Pb. 

Li. 

Mg. 

Mn. 

Hg. 

Mo. 

Ni. 

Nb. 

N. 

Os. 

0. 

Pd. 

P. 

Pt. 

K. 

Ph. 

Rb. 

Ru. 


27.5 
120 

75 
137.2 
210 

11 

79.952 
112 
132.6 

40 

12 
138 

35.457 

52.4 

59 

63.5 
144.78 
162 

19 

69.9 

13.8 
197 
1 
113.4 
126.85 
197.2 

56 
139 

206.92 
7 

24 

55.2 
200 

96 

59 

94 

14.044 
200 

16 
106.5 

31 
198 

39.137 
104 

85.4 
104 


0.2143 

0.05077 
0.08140 

0.03084 
0.3663 
0.08432 
0.05669 

0.17* 
0.4589 
0.04479 
0.093 

0.10696 
0.09515 
0.04563 

0.0802 

0.4079 

0.03244 

2.41 

0.057 

0.05412 

0.03259 

0.11379 

0.04485 

0.03140 

0.9408 

0.2499 

0.1217 

0.03332 , 

0.07218 

0.10863 

0.1652 

0.03113 

0.145 

0.0593 

0.1887 

0.03244 

0.1655 

0.05803 

• • • • 


5.89 


Antimony 


6.09 


Arsenic 


6.10 


Barium 




Bismuth 


6.48 


Boron 


3.99 


Bromine 


6.74 


Cadmium 


6.35 


Caesium 




Calcium 


6.80 


Carbon 


5.51 


Cerium 


6.18 


Chlorine 


3.30 


Chromium 




Cobalt 


6.31 


Copper 


6.04 


Didvmium 


6.60 


Erbium 




Fluorine 




Gallium 


5.61 


Glucinum 


5.63 


Gold 


6.39 


Hydrogen 


2.41 


Indium 


6.46 


Iodine 


6.87 


Iridium 


6.43 


Iron 


6.37 




6.23 




6.50 


Lithium 


6.58 


Magnesium 


6.00 


Manganese 


6.72 


Mercury 


6.66 




6.93 


Nickel 


6.41 


Niobium 




Nitrogen 


2.32 


Osmium 


6.23 


Oxygen 


2.32 


Palladium 


6.32 


Phosphorus 


5.85 


Platinum 


6.42 


Potassium 


6.48 


Rhodium 


6.04 




• • • • 



ATOMIC AND MOLECULAR WEIGHTS VALENCE. 



13 



ELEMENTS— Continued. 



Name. 


A. 
Symbol. 


B. 

Atomic 
weight. 


C. 
Specific heat. 


D. 

Atomic 
heat. 
BxC. 


Selenium 


Se. 
Si. 

A g- 

Na. 

Sr. 

S. 

Ta. 

Te. 

Tl. 

Th. 

Sn. 

Ti. 

W. 

U. 

V. 

Y. 

Zn. 

Zr. 


79 

28 
107.93 

23.043 

87.5 

32.075 
137.6 
128 
204 
234 
118 

50 
184 
120 

51.3 

92.5 

65.2 

89.6 


0.08468 
0.2029 
0.05701 
0.2934 

0.20259 

0.05i55 
0.03355 

0.05623 

0.03342 

0.09555 
0.0666 


6.69 


Silicon 


5.68 


Silver 


6.15 


Sodium 


6.76 


Strontium 




Sulphur 


6.50 


Tantalum 


6.59 


Thallium 


6.84 


Thorium . . . . , 




Tin 


6.63 


Titanium 




Tungsten 


6.15 


Uranium 












Zinc 


6.23 


Zirconium 


5.97 







We are not limited to chemical means in fixing atomic weights; in- 
deed, cases frequently arise in which the results of numerous analyses are 
such as would agree with one or more numbers equally well. In these 
cases we obtain valuable indications from the physical properties of the 
substances whose atomic weights are not clearly definable by chemical 
means. 

A most valuable aid in this respect is the law of Dulong and Petit. 
These observers found, in 1819, that there existed a definite relation be- 
tween the atomic weight of an element and its specific heat (see p. 30), 
and that the product obtained by multiplying these two quantities to- 
gether was, with a few exceptions, nearly constant. While the atomic 
weights differ greatly from each other — 7 and 234 being the extremes — 
the specific heats differ in an opposite manner, and to such an extent 
that the product obtained by multiplying the two together does not 
vary much from 6.4. This product is given for each element in the 
above table as its atomic heat. 

If by analytical means we are unable to determine which of two 
numbers is the correct atomic weight of an element, we determine its 
specific heat and select that one of the two numbers under consideration 
which, when multiplied by the specific heat, gives a result most nearly 
approaching 6.4. 

It will be noticed, on examining the table, that the atomic heats of 
certain of the elements vary considerably from the rule. The atomic 
heats of carbon, boron, silicon, sulphur, and phosphorus are subject to- 
great variations, as will be seen in the following table : 



14 GENERAL MEDICAL CHEMISTRY. 

Specific Atomic 

_ heat. heat. 

Boron. 

Crystallized at— 39.6° 0.1915 2.11 

Crystallized at-f 76.7° 0.2737 3.01 

Crystallized at+233.2° 0.3663 3.99 

Amorphous 0.255 2.81 

Carbon. 

Diamond at— 50.5° 0.0635 0.76 

Diamond at +140° 0.2218 2.66 

Diamond at +985° 0.4589 5.51 

Graphite at- 50.3° 0.1138 1.37 

Graphite at+138.5° 0.2542 3.05 

Graphite at+977.9° 0.4670 5.60 

Wood charcoal 0.2415 2.90 

Silicon. 

Crystallized at - 39.8° 0.1360 3.81 

Crystallized at+128.7° 0.1964 5.50 

Crystallized at + 232.4° 0.2029 5.68 

Fused at + 100° 0.175 4.90 

Sulphur. 

Orthorhombic at+ 45° 0.163 5.22 

Orthorhombic at+ 99° 0.1776 5.68, 

Liquid at + 150° 0.234 7.49 

Recently fused at + 98° 0.20259 6.48 

Phosphorus. 

Yellow at- 78° 0.174 5.39 

Yellow at+ 36° 0.202 6.26 

Liquid at + 100° 0.212 6.57 

Amorphous at+ 98° 0.170 5.27 

It will be observed that, as the temperature of the solid element is 
increased, the atomic heat more nearly approaches 6.4. It will further 
be noticed that those elements with which the perturbations occur are 
precisely those which are capable of existing in two or more allotropic 
forms (see p. 30). As in the passage of an element from one allotropic 
condition to another, absorption or liberation of heat always takes place, 
as the result of " interior work ; " it is more than probable that these 
perturbations are due to a constant tendency of the element to pass from 
one allotropic condition to another. 

The atomic heats of those elementary gases which have only been 
liquefied by enormous cold and pressure are tolerably constant at about 
2.4. 

Other considerations of a physical nature having a bearing upon the 
atomic weights will be considered later. 

Molecular weight. — The molecular weight of a substance is the weight 
of its molecule as compared with the weight of an atom of jiydrogen. It 
is also, obviously, the sum of the weights of all the atoms making up the 
molecule. 

The determination of molecular weight is chiefjy of importance in the 
study of the compounds of carbon. We can readily determine the per- 
centage composition of an organic body by analysis; this does not, 
however, indicate the number of atoms of each of the constituent ele- 



ATOMIC AND MOLECULAR WEIGHTS— VALENCE. 15 

ments. For example, if we analyze the gas acetylene, and the liquid 
benzene, we obtain the following results: 

Acetylene. Benzene. 

Carbon 92.31 92.31 24 

Hydrogen 7.69 7.69 2 



100.00 100.00 26 

Upon further examination we find the molecular weight of acetylene 
to be 26, and consequently we know its molecule to consist of two atoms 
of carbon and two of hydrogen. The molecular weight of benzene, on the 
other hand, being 78, or 26 x 3, we know that its molecule consists of six 
atoms each of carbon and hydrogen. 

A very ready means of determining the molecular weight of any sub- 
stance which we can convert into a gas is based upon Avogadro's law. 
The specific gravity of a gas is the weight of a given volume as compared 
with that of an equal volume of hydrogen. But these equal volumes con- 
tain equal numbers of molecules (p. 10), and therefor, in determining 
the specilic gravity of a gas, we obtain the weight of its molecule as com- 
pared to that of a molecule of hydrogen; and, as the molecule contains 
two atoms of hydrogen, while one atom of hydrogen is the unit of com- 
parison, it follows that the specific gravity of a gas, multiplied by two, is 
its molecular weight. 



VALENCE, OR ATOMICITY. 

By the valence of an element is understood the combining capacity 
of its atoms. We know that 

One atom of chlorine combines with one atom of hydrogen, 
One atom of oxygen combines with two atoms of hydrogen, 
One atom of nitrogen combines with three atoms of hydrogen, 
One atom of carbon combines with four atoms of hydrogen, 

and that the atoms of different elements thus possess different powers of 
holding hydrogen in combination. In the compounds formed by the 
above unions chlorine is univalent, oxygen is divalent, nitrogen is trival- 
ent, and carbon is quadrivalent. 

But the valence of the elements is not fixed and invariable. Thus, 
while chlorine and iodine each combine with hydrogen, atom for atom, and 
in those compounds are consequently univalent, they unite with each 
other to form two compounds — one containing one atom of iodine and one 
of chlorine, the other containing one atom of iodine and three of chlorine; 
chlorine being univalent, iodine is obviously trivalent in the second of 
these compounds. Again, phosphorus forms two chlorides, one containing 
three, the other five atoms of chlorine, to one of phosphorus. 

In view of these facts, we must consider, either: 1, that the valence of 
an element is that which it exhibits in its most saturated compounds, as 
phosphorus in the pentachloride, and that the lower compounds are non- 
saturated and have free valences; or 2, that the valence is variable. The 
first supposition depends too much upon the chances of discovery of com- 
pounds in which the element has a higher valence than that which might 



16 GENERAL MEDICAL CHEMISTRY. 

be considered as the maximum to-day. The second supposition — notwith- 
standing the fact that, if we admit the possibility of two distinct valences, 
we must also admit the possibility of others — is certainly the more tenable 
and the more natural. In speaking, therefor, of the valence of an ele- 
ment, we must not consider it as an absolute quality of its atoms, but 
simply as their combining power in the particular class of compounds 
under consideration. Indeed, compounds are known in whose molecules 
the atoms of one element exhibit two distinct valences; thus, ammonium 
cyanate contains two atoms of nitrogen: one in the ammonium group is 
quinquivalent, one in the acid radical is trivalent. 

It has been found that, in the great majority of instances in which an 
element exhibits different valences, they differ from each other by two. 
Thus, phosphorus is trivalent or quinquivalent; platinum is divalent or 
quadrivalent. 

The valence of an atom is expressed in notation by signs placed above 
and to the right of the symbol (see below), thus: CI', univalent; O", diva- 
lent; N'", trivalent; C iv , quadrivalent; P v , quinquivalent; (Fe 2 ) vi , hexaval- 
ent. 

Symbols — Formulae — Equations. 

Symbols. — These are conventional abbreviations of the names of the 
elements, whose purpose it is to introduce simplicity and exactness into 
descriptions of chemical actions. They consist of the initial letter of the 
Latin name of the element, to which is usually added one of the other 
letters. If there be more than two elements whose names begin with the 
same letter, the single-letter symbol is reserved for the commonest ele- 
ment. Thus, we have nine elements whose names begin with C; of these 
the commonest is Carbon, whose symbol is C; the others have double- 
letter symbols, as Chlorine, CI; Cobalt, Co; Copper, Cu (Cuprum), etc. 

These symbols do not indicate simply an indeterminate quantity, but 
one atom of the corresponding element. When more than one atom is 
spoken of, the symbol is not repeated, but the number of atoms which it is 
desired to indicate is written either before the symbol, or, in small figures, 
after and below it; thus, H indicates one atom of hydrogen; 2C1, two 
atoms of chlorine; C 4 , four atoms of carbon, etc. 

Formulae. — What the symbol is to the element, the formula is to the 
compound; by it the number and kind of atoms of which the molecule of 
a substance is made up are indicated. The simplest kind of formulae are 
what are known as empirical formulae; which indicate only the kind 
and number of atoms which form the compound. Thus, HC1 indicates a 
molecule composed of one atom of hydrogen united with one atom of 
chlorine; 5H 2 0, five molecules, each composed of two atoms of hydro- 
gen and one atom of oxygen, the number of molecules being indicated 
by the proper numeral placed before the formula, in which place it applies 
to all the symbols following it. Sometimes it is desired that a numeral 
shall apply to a part of the following symbols only, in which case they 
are enclosed in parentheses, thus: 3(S0 4 )A1 2 , means 3 times S0 4 and 
twice Al. This may also be written (S0 4 ) 3 A1 2 . 

For the other varieties of formulae, see p. 23. 

Equations are combinations of formulae and algebraic signs so arranged 
as to indicate a chemical reaction and its results. The signs used are the 
plus and equality signs; the former being equivalent to "and," and the 
second meaning " have reacted upon each other and have produced." The 



RADICALS ACIDS BASES AND SALTS. 17 

substances entering into the reaction are placed before the equality sign 
and the products of the reaction after it; thus, the equation 

2KHO + S0 4 H 2 = S0 4 K 2 + 2H 2 

means, when translated into ordinary language: two molecules of pot- 
ash, each composed of an atom of potassium, one atom of hydrogen and 
one atom of oxygen, and one molecule of sulphuric acid, composed of 
one atom of sulphur, four atoms of oxygen and two atoms of hydrogen, 
have reacted upon each other and have produced one molecule of potas- 
sium sulphate, composed of one atom of sulphur, four atoms of oxygen 
and two atoms of potassium, and two molecules of water, each composed 
of two atoms of hydrogen and one atom of oxygen. The saving of time 
and labor by the use of symbols is obvious from this example. As no 
material is ever lost or created in a reaction, the number of each kind of 
atom occurring before the equality sign in an equation must always be 
the same as that occurring after it. 



Radicals — Acids — Bases and Salts. 

Radicals. — In the molecules of compound substances the atoms are 
not placed at random, but certain of them are attached more closely to 
each other than they are to the remainder; and most, if not all, com- 
pounds contain within the molecule a group of atoms, whose valences 
are not all satisfied, and in which the atoms are so closely linked that the 
entire group is capable of passing readily from one combination to an- 
other unchanged, although it is not necessarily capable of a separate 
existence; such a group is called a radical. Marsh-gas, for instance, has 
the empirical formula CH 4 . By acting upon this substance in suitable 
ways, we can cause the atom of carbon, accompanied by three of the 
hydrogen atoms, to pass unchanged into a variety of other substances, 
such as: (CH 3 )C1; (CH 3 )OH; (CH 3 ) 2 0; C 2 H 3 2 (CH 3 ), etc.; we therefor 
consider marsh-gas as made up of the radical (CH 3 ) combined with an 
atom of hydrogen, (CH 3 )H. It is usual to enclose the radical in brackets 
or parentheses to indicate its nature. 

Like the elements, the radicals possess different valences, depending 
upon the number of unsatisfied elementary valences which they contain. 
Thus, in the radical (CH 3 ) three of the four valences of the atom of car- 
bon are satisfied by three atoms of hydrogen; the remaining free valence 
of the carbon atom renders the radical univalent; it gives it a power of 
combination equal to that of an atom of a univalent element. These 
radicals play an important part in the chemistry of the carbon compounds. 

Acids. — It is a difficult matter to give a concise definition of an acid, 
which shall cover the meaning fully. The usual definition is " a compound 
of an electro-negative radical with hydrogen, which hydrogen it can part 
with in exchange for a metal or basylous radical," which is probably as 
satisfactory a definition as can be given at present. The two character- 
istics of an acid being that it contains, on the one hand, an electro-nega- 
tive radical or element, and, on the other hand, hydrogen capable of being 
replaced by an electro-positive radical or element. The atoms of hydro- 
gen so replaceable are termed the basic or replaceable hydrogen of the 
acid, the acid itself being designated as monobasic, dibasic, tribasic, te~ 
trabasic, etc., according as it contains one, two, three, four, etc., atoms of 
such replaceable hydrogen. 
9 



18 



GENERAL MEDICAL CHEMISTRY. 



By electro-positive or basylous elements or radicals are meant such as 
are disengaged at the zinc or negative pole, when their compounds are 
decomposed by the action of the galvanic battery. 

By electro-negative or acidulous are meant such as are disengaged at 
the platinum or positive pole under like circumstances. In the following 
table are given the electric conditions of the more important elements and 
radicals: 



Electro-positive, or Basylous. 



Electro-negative, or Acidulous. 



Hydrogen. 

Potassium. 

Sodium. 


Copper. 

Mercury. 

Tin. 


Oxygen. 

Fluorine. 

Chlorine. 


Arsenic. 

Antimony. 

Boron. 


Lithium. 


Iron. 


Bromine. 


Carbon. 


Silver. 


Cobalt. 


Iodine. 


Silicium. 


Ammonium. 

Calcium. 

Barium. 


Nickel. 

Gold. 

Bismuth. 


Sulphur. 

Selenium. 

Tellurium. 


Molybdenum. 
Tungsten, 

and their oxidized 


Zinc. 


Platinum . 


Nitrogen. 


radicals. 


Magnesium. 
Cadmium. 


Aluminium. 
Chromium. 


Phosphorus. 


Cyanogen. 


Lead. 


Alcoholic radicals. 







Bases. — A base is a compound of hydrogen and oxygen with an elec- 
tro-positive element or radical, which it is capable of giving up in exchange 
for the hydrogen of an acid; indeed, it may be considered as one or more 
molecules of water, in which one-half the hydrogen has been replaced by 
an electro-positive element or radical. Thus, KHO, potassium hydrate; 
(NHJHO, ammonium hydrate. These substances, being considered as 
derived from water, are called hydrates; they are, according to existing 
views, the only substances to which the term base properly applies. 

Bases and acids are capable of what is called double decomposition 
with each other. That is, the acid and base are both decomposed, while 
water and a salt are formed : 

KHO + N0 3 H = H 2 + NO.K. 

Potassium Nitric Water. Potassium 

hydrate. acid. nitrate. 

Salts are substances formed by the substitution of basylous radicals 
or elements for a part or all of the replaceable hydrogen of an acid. 
They are always formed, therefor, when bases and acids enter into 
double decomposition. They are not, as was formerly supposed, formed 
by the union of a metallic with a non-metallic oxide, but, as stated above, 
by the substitution of one or more atoms of an element or radical for the 
hydrogen of the acid. Thus, the compound formed by the action of sul- 
phuric acid upon quicklime is not S0 3 CaO, but S0 4 Ca, formed by the 
interchange of atoms 

S 

4 < (Ca 

H 2 ) > O 

and not 

S 

/Ca 



<- 



O 



<^ 



o 



RADICALS ACIDS BASES AND SALTS. 19 

for which reason it is not the sulphate of lime, as it was formerly called, 
but calcium sulphate. 

The basylous element of a salt is endowed with considerable mobility, 
and may be readily transferred from one acid radical to another; or liber- 
ated by the presence of an acid radical with which it has a greater ten- 
dency to unite (for which it has a greater affinity), or of an element whose 
tendency to unite with its acidulous radical is greater than its own. Thus, 
if sodium sulphate and barium nitrate be brought together in solution, 
the following double decomposition occurs: 

S0 4 Na 2 + (N0 3 ) 2 Ba=S0 4 Ba+2N0 3 Na. 

Again, silver is separated from the nitrate by the presence of mercury; 
lead from its acetate in the presence of zinc; copper from its sulphate in 
the presence of iron, etc. 

If two acids be brought in the presence of a single base, the latter is 
divided by the former according to their affinities, subject to the modifi- 
cations due to the volatility of the acid, or its insolubility, or the insolu- 
bility of the salt formed. 

If one of the acids be volatile at the temperature at which the reac- 
tion occurs, it is driven off. Sodium nitrate and sulphuric acid may 
exist together at ordinary temperatures, but upon heating the mixture 
the nitric acid is driven off and sodium sulphate is formed. 

If one of the acids be insoluble, its influence becomes nil — it separates 
in the solid form while the other takes its place; thus, if potassium silicate 
and hydrochloric acid be brought together, potassium chloride remains in 
the solution and silicic acid separates. 

Whenever two salts in solution are brought together, the basylous 
element of one of which is capable of uniting with the acidulous radical 
of the other to form an insoluble salt, the insoluble compound is formed. 
Thus, if a solution of a sulphate be added to a solution of a barium salt, 
the insoluble barium sulphate is precipitated. 

What has been stated of two acids in presence of one base also ap- 
plies to two bases in presence of one acid. 

The term salt, as used at present, applies to the compound formed by 
the substitution of another element for the hydrogen of any acid; and 
indeed, as used by some authors, to the acids themselves, which are con- 
sidered as salts of hydrogen. It is probable, however, that eventually 
the name will be limited to such compounds as correspond to acids whose 
molecules contain more than, two elements. Indeed, from the earliest 
times of modern chemistry, a^distinction was observed between the haloid 
salts, i. e., those the molecules of whose corresponding acids consisted of 
hydrogen united with one other element, on the one hand; and the salts 
of the oxacids, i. e., those into whose composition oxygen entered, on the 
other hand. This distinction, however, has gradually fallen into the back- 
ground, for the reason that the methods and conditions of formation of 
the two kinds of salts are usually the same when the basylous element be- 
longs to that class of elements usually designated as metallic. 

There are, nevertheless, important distinctions between the two kinds 
of salts, which we believe to be of sufficient importance not only to men- 
tion, but to make a factor in the classification of the elements (see p. 26). 
The salts of the hydracids (haloid salts) maybe readily obtained without 
the previous formation of the acid, as potassium unites directly with 
•chlorine to form potassium chloride. The salts of the oxacids, on the 



20 GENERAL MEDICAL CHEMISTRY. 

other hand, are only formed by the substitution of the basylous element 
for the hydrogen of the previously formed acid, by some double decom- 
position or by the oxidation of an existing compound, in all cases in which 
the corresponding acid is capable of separate existence. There are, for 
example, three methods of formation of potassium sulphate: either by the 
action of the basylous element or its hydrate upon sulphuric acid — 

S0 4 H 2 +K 2 = S0 4 K 2 + H 2 
S0 4 H 2 + 2KHO = S0 4 K 2 + 2H 2 ; 

or by double decomposition — 

2N0 3 K + S0 4 H 2 = S0 4 K 2 + 2N0 3 H ; 

or by the oxidation of the sulphide — 

SK 9 + 20„ = S0 4 K S . 

In those cases in which the acid corresponding to the salt has not 
been obtained, it is more than probable that the formation of the acid 
precedes that of the salt. The true carbonic acid, for instance, C0 3 H 2 , is 
not known, yet its anhydride, C0 2 , is capable of forming salts; but, as the 
formation of these salts occurs only in the presence of water, we may infer 
that the reaction 

0O 2 + H 2 O = CO 3 H 2 

occurs before the formation of the salt. 

An important difference between the two classes of compounds, and 
one which we have utilized in our classification of the elements, is that, 
while there exist compounds of all the elements corresponding to the 
hydracids, there are many elements which are not capable of replacing 
the hydrogen of the oxacids to form salts; and those elements, thus in- 
capable of forming oxysalts, are strongly electro-negative, and their ox- 
ides are capable of uniting with water to form acids (see p. 27). 

Nomenclature . 

The names of the elements are mostly of Greek derivation, and have 
their origin in some prominent property of the substance; thus, phos- 
phorus, (puis, light, and <j>€p€iv, to bear. Some are of Latin origin, as silicon, 
from silex, flint; some of Gothic origin, a.s fron, from iarn; and others are 
derived from modern languages, as p>otassium, from pot-ash. Very little 
system has been followed in naming the elements, beyond applying the 
termination ium to the metals, and ine or on to the metalloids; and even 
to this rule we find such exceptions as a metal called manganese and a 
metalloid called sulphur. 

The names of compound substances were formerly chosen upon the 
same system, or rather lack of system, as those of the elements. So long 
as the number of compounds with which the chemist had to deal remained 
small, the use of these fanciful appellations, conveying no more to the 
mind than perhaps some unimportant quality of the substances to which 
they applied, gave rise to comparatively little inconvenience. In these 
later days, however, when the number of compounds has risen high in the 
thousands, some systematic method has become absolutely necessary. 



NOMENCLATURE. 2 1 

The principle at the base of the system of nomenclature at present used 
is that the name shall itself convey, as far as possible, the composition and 
character of the substance. 

Compounds consisting of two elements, or of an element and a radical 
only, binary compounds, are designated by compound names made up of 
the name of the more electro-positive, followed by that of the more elec- 
tro-negative, in which the termination ide has been substituted for the 
terminations ine, on, ogen, ygen, orus, turn, and ur. For example: the 
compound of potassium and chlorine is called potassium chloride, that of 
potassium and oxygen, potassium oxide, that of potassium and phos- 
phorus, potassium phosphide. 

In a few instances the older name of a compound is used in preference 
to the one which it should have under the above rule, for the reason that 
the substance is one which is typical of a number of other substances, 
and therefor deserving of exceptional prominence; such are ammonia, 
NH 3 ; water, H 2 0. 

When, as frequently happens, two elements unite with each to form 
more than one compound, these are usually distinguished from each other 
by prefixing to the last word of the name the Greek numeral correspond- 
ing to the number of atoms of the element designated by that word, as 
•compared with a fixed number of atoms of the other element. 

Thus, in the series of compounds of nitrogen and oxygen, most of 
which contain two atoms of nitrogen, N 2 is the standard of comparison, 
and consequently the names are as follows: 

N 2 = Nitrogen monoxide. 

NO ( = N 2 2 ) = Nitrogen ^"oxide. 
N 2 3 = Nitrogen £noxide. 

N 2 ( = N 2 4 )= Nitrogen tetfroxide. 
N 2 5 = Nitrogen jt?e?z£oxide. 

Another method of distinguishing two compounds of the same two 
•elements consists in terminating the first word in ous in that compound 
which contains the less proportionate quantity of the more electro-nega- 
tive element, and in ic in that containing the greater proportion; thus: 

I 

50 2 = Sulphurous oxide. 

50 3 — Sulphuric oxide. 

Hg 2 Cl 2 (2Hg : 2Cl)=MercuroM« chloride. 
HgCl 2 (2Hg : 4C1) =Mercure"c chloride. 

This method, although used to a certain extent in speaking of compounds 
composed of two elements of Class II. (see p. 27), is used chiefly in speak- 
ing of binary compounds of elements of different classes. 

In naming the oxacids the word acid is used, preceded by the name 
of the electro-negative element other than oxygen, to which a prefix or 
suffix is added to indicate the degree of oxidation. If there be only two, 
the least oxidized is designated by the suffix ous, and the more oxidized 
by the suffix ic, thus: 

N0 2 H=NitroMS acid. 
N0 3 H=Nitrzc acid. 

If there be more than two acids, formed in regular series, the least oxi- 



22 GENERAL MEDICAL CHEMISTRY. 

dized is designated by the prefix hypo and the suffix ous; the next by the 
suffix ous/ the next by the suffix ic/ and the most highly oxidized by the 
prefix per and the suffix ic/ thus: 

ClOH =^Hyp>oc\AoTOus acid. 
ClO 2 H:=Chlor0i4S acid. 
C10,H= Chloric acid. 
C10 A H=jPerchlor£c acid. 

Certain elements, such as sulphur and phosphorus, exist in acids which 
are derived from those formed in the regular way, and which are specially 
designated (see pp. 88, 112). 

The names of the salts are derived from those of the acids by drop- 
ping the word acid, changing the termination of the other word from ous 
into ite, or from ic into ate, and prefixing the name of the electro-positive 
element or radical; thus: 

SO s H B SO,K 3 

Sulphurows acid. Potassium sulphite. 

S0 4 H 2 S0 4 K 2 

Sulphuric acid. Potassium sulphate. 

ClOH ClOK 

Hypochlorous acid. Potassium hypochlorite. 

Acids whose molecules contain more than one atom of replaceable hy- 
drogen are capable of forming more than one salt with electro-negative 
elements, or radicals, whose valence is less than their basicity. Ordinary 
phosphoric acid, for instance, contains in each molecule three atoms of 
basic hydrogen, and consequently is capable of forming three salts by the 
replacement of one, two, or three of its hydrogen atoms by one, two, or 
three atoms of a univalent element; to distinguish these the Greek pre- 
fixes mono, di, and tri are used thus: 

P0 4 H 2 K=Jf/bwopotassic phosphate, 
P0 4 HK a = Z>£potassic phosphate. 
P0 4 K 3 = TWpotassic phosphate. 

The first is also called cfc'Ayc??*opotassic phosphate, and the second hydrodi- 
potassic phosphate. 

In the older works, salts in which the hydrogen has not been entirely 
displaced are sometimes called fo'salts (bicarbonates), or acid salts; those 
in which the hydrogen has been entirely displaced being designated as 
neutral salts. 

A few elements, such as mercury, copper, and iron, form two distinct 
series of salts; these are distinguished, in the same way as the acids, by 
the use of the suffix ous in the names of those containing the less propor- 
tion of electro-negative group and the suffix ic in those containing the 
greater proportion, e. g. : 

S0 4 (Cu 2 ) 2 (1S0 4 : 4Cu)=Cuprow* sulphate. 

S0 4 Cu 2 " (2S0 4 : 4Cu)=:Cupric sulphate. 

S0 4 Fe (2S0 4 : 2Fe) = Ferrous sulphate. 

(S0 4 ) 3 Fe 2 (3S0 4 : 2Fe)=Femc sulphate. 

The names, basic salts, sz^salts, and oxysailts have been applied in- 
differently to salts, such as the lead subacetates, which are compounds- 



TYPICAL FOKMUL^E AND FORMULAE OF CONSTITUTION. 23 

containing the normal acetate and the hydrate or oxide of lead; and to 
salts such as the so-called bismuth subnitrate, which is a nitrate, not of 
bismuth, but of the univalent radical (Bi'"0")'. 

By double salts are meant such as are formed by the substitution of 
different elements or radicals for two or more atoms of replaceable hydro- 
gen of the acid, such as ammonio-magnesian phosphate, P0 4 Mg" (NH 4 )'. 



Oxides, Hydrates, and Chlorides. 

The oxides, hydrates, and chlorides of the various elements differ 
from each other materially in their properties. The oxides of a certain 
class of elements, when they unite with water, form hydrates which pos- 
sess acid properties; such oxides are called anhydrides. The oxides of 
another class of elements unite with water to form hydrates endowed with 
strongly basic properties. Between these two classes is a third, some 
of whose oxides form hydrates which are basic in character, while others 
unite with water to form acids (see p. 27). 

As a rule, those elements which form basic hydrates also form chlo- 
rides which are either insoluble in water, or soluble without decomposition. 
Those elements, on the other hand, whose oxides are all anhydrides, form 
chlorides which are decomposed when they come in contact with water. 



Typical Formulae and Formulae of Constitution. 

The formulae which we have hitherto used, and which are known as 
empirical formulas, indicate only the number and kind of atoms consti- 
tuting the molecule — indications which would seem at first sight to be all 
that could be required of them. When, however, it was found that two 
substances existed, each composed of the same kind and number of atoms, 
and yet possessing very different physical and chemical properties, the 
inference naturally followed that these differences must be due to a dif- 
ferent arrangement of the atoms within the molecule — a different consti- 
tution, as it is called. To indicate these differences extended formulae 
were devised: typical for 'mula?, which show only the more salient points 
of the constitution of the substance; and graphic formula?, or formulce 
of constitution, which are intended to set forth the entire structure of the 
molecule. 

The idea of chemical types was first suggested by Dumas in 1839. In 
the system of typical formulae all substances are considered as being so 
constituted that their rational formulas may be referred to one of three 
classes or types, or to a combination of two of these types. These three 
classes, being named after the most common substance occurring in each, 
are expressed thus: 



The hydrogen 


The water 


The ammonia 


type. 


type. 


type. 


H l 


S}° 


H ) 


Hf 


h[-n 






h[ 


H *i 


S;l». 


HJ 


HJ 


H S [N, 


etc., 


etc., 


hJ 

etc., 



24 GENERAL MEDICAL CHEMISTRY. 

it being considered that the formula of any substance of known consti- 
tution can be indicated by substituting the proper element, or radical, for 
one or more of the atoms of the type, thus: 

en (c,h.)'i (c a H 6 n a, 

HI H | u H V N Ca 



(C.H.)' 1 (O.H.)' ) 
H( u HV 

H 




Hydrochloric Alcohol. Ethylamine. Calcium Sulphuric 

acid. chloride. acid. 

Typical formulae are of great service in the classification of compound 
substances, as well as to indicate, to a certain degree, their nature and 
the method of the reactions into which they enter. 

Referring, for instance, to the formula of marsh-gas, given on p. 17, 
as (CH 3 ) H, we find that it belongs to the same type as hvdrogen, and 

pTT \ 

that its typical formula is t| r • This formula indicates not only that 

the substance is composed of the univalent radical CH 3 with an atom of 
hydrogen, but also that the extra-radical atom of hydrogen, being united 
to an electro-positive radical, is not replaceable after the manner of the 
basic hydrogen of an acid, although it may be replaced by an electro- 
negative element, such as chlorine. The radical CH 3 is also capable of 
removal and passage into other forms of combination ; it may be made to 

/-ITT '. PIT ) 

pass from the compound -rj [ into that having the composition pj >- , 

PIT ) 
and from that into yj t O. The last formula indicates a substance 

which is of the same type as water, and is consequently the hydrate of 
the radical, a hydrate which, owing to the electro-positive character of 
the radical, is not acid. If, however, the radical be oxidized, it becomes 

electro-negative, and the resulting substance, ^ " -/r j- O, is endowed with 

acid properties, and, as the typical formula indicates, contains a single 
atom of basic hydrogen. 

There are two substances which, on analysis, each prove to have the 
composition C 2 H 4 2 , and which, nevertheless, differ from each other 
widely in their properties. By a further examination of these two sub- 
stances, we find that one contains the group (CH 3 )', while the other con- 
tains the group (C 2 H 3 0)', united to one atom of replaceable hydrogen. 
The difference in their constitution at once becomes apparent in their 

typical formulae, ^?<SPy [ O and ( C 2 H 3 °^ I Q, which also indicate differ- 
ences in their properties, which we find upon experiment to exist. The 
first substance is neutral in reaction and possesses no acid properties; it 

closely resembles a salt of an acid having the formula ^ jl > O. The 

second substance, on the other hand, has a strongly acid reaction, and 
markedly acid properties, as indicated by the oxidized radical and the 
extra-radical hydrogen. It is capable of forming salts by the substitution 
of an atom of a univalent basylous element for its single replaceable atom 

of hydrogen ^ 2 3 ^j' v O. Again, the action which takes place between 

caustic potash and acetic acid is indicated more accurately and intelli- 
gibly by the typical equation — 



TYPICAL FORMULA AND FORMULAE OF CONSTITUTION. 



25 



K 



O 



C.JLO 



O 



H 



O 



°* H £ 1 O, 



K 



H f w ^ "H J" w ~ H 

than by the empirical equation — 

KHO + C 2 H 4 2 =H 2 + C 2 H 3 2 K. 

Although typical formulae have been, and still are, of great service, 
many cases arise, especially in treating of the more complex organic sub- 
stances, in which they do not sufficiently indicate the relations between 
the atoms which constitute the molecule, and thus fail to convey a proper 
idea of the nature of the substance. Considering, for example, the ordi- 
nary lactic acid, we find its composition to be C 3 H 6 3 , which, expressed 

(C* FT OV ) 
typically, would be ^ 3 4 A [ 2 , a constitution supported by the fact 

that the radical (C 3 H 4 0)" may be obtained in other compounds, as 

4 PI i * ^ n ^ s constitution, however, cannot be the true one, because 

in the first place, lactic acid is not dibasic, but monobasic; and, in the 
second place, there is another acid, called paralactic acid, having an iden- 
tical composition, yet differing in its products of decomposition. These 
differences in the properties of the two acids must be due to a different 
arrangement of atoms in their molecules, a view which is supported by 
the sources from which they are obtained and the nature of their products 
of decomposition. 

To express the constitution of such bodies, graphic formulae are used, 
in which the position of each atom in relation to the others is set forth. 
The constitution of the two lactic acids would be expressed by graphic 
formulae in this way: 



or, 



C^-H 

Ko-h 

L/o 

°\0— H 



CH 3 

CH.OH 

CO.OH 

Ordinary 
lactic acid. 



C^-H 



and 



C 



and 



X 0— H 

/H 
\H 



I/O 
°\0— H 



CH 2 OH 

I 

CH 2 

CO.OH 

Paralactic 
acid. 



It must be understood that these graphic formulae are simply in- 
tended to show the relative attachments of the atoms, and are in nowise 
intended to convey the idea that the molecule is spread out upon a flat 
surface with the atoms arranged as indicated in the diagram. The for- 
mula of ordinary lactic acid shows that one of its atoms of carbon has 
three of its valences satisfied by three atoms of hydrogen, and is attached 
by its remaining valence to another atom of carbon, one of whose other 



26 GENERAL MEDICAL CHEMISTRY. 

valences is satisfied by an atom of hydrogen, another by the univalent 
group OH, and whose remaining valence attaches it to the third atom 
of carbon, two of whose remaining valences are satisfied by one atom of 
the divalent element oxygen, and the last by the group OH. 

Great care and much labor are required in the construction of these 
graphic formulae, the positions of the atoms being determined by a close 
study of the methods of formation, and of the products of decomposition 
of the substance under consideration. Naturally, in a matter of this na- 
ture, there is always room for differences of opinion — indeed, the entire 
atomic theory is open to question, as is the theory of gravitation itself; 
but, whatever may be advanced, two facts cannot be denied : first, that 
chemistry owes its advancement within the past half -century to the atomic 
theory, which to-day is more in consonance with observed facts than any 
substitute which can be offered ; second, that without the use of graphic 
formulae it would be impossible to offer any adequate explanation of the 
reactions which we observe in dealing with the more complex organic sub- 
stances. 

In chemistry, as in other sciences, a sharp distinction must always be 
made between facts and theory: the former, once observed, are immut- 
able additions to our knowledge; the latter are of their nature subject to 
change with our increasing knowledge of facts. We have every reason 
for believing, however, that the supports upon which the atomic theory 
rests are such that, although it may be modified in its details, its essential 
features will remain unaltered. 



Classification of the Elements. 

The necessity of a classification of the elements into groups for con- 
venience of study was felt early in the history of chemistry. Berzelius 
was the first to divide all the elements into two great classes, to which he 
gave the names metals and metalloids. The metals, being such substances 
as are opaque, possess what is known as metallic lustre, are good con- 
ductors of heat and electricity, and are electro-positive; the metalloids y 
on the other hand, such as are gaseous, or, if solid, do not possess metallic 
lustre, have a comparatively low power of conducting heat and electri- 
city, and are electro-negative. 

This division, based, as it will be seen, purely upon physical proper- 
ties, which, in many cases, are ill-defined, has become insufficient. Sev- 
eral elements formerly classed under the above rules with the metals, such 
as arsenic and antimony, resemble phosphorus in their chemical characters 
much more clearly than they do any of the metals; indeed, by the char- 
acters mentioned above, it is impossible to draw any line of demarcation 
which shall separate the elements distinctly into two groups. 

The classification of the elements should be such that each group shall 
contain elements whose chemical properties are similar — the physical prop- 
erties being considered only in so far as they are intimately connected with 
the chemical (see p. 13). The arrangement of elements into groups is not 
equally easy in all cases; some groups, as the chlorine group, are sharply 
defined, while the members of others differ from each other more widely 
in their properties. The positions of most of the more recently discovered 
elements are still uncertain, owing to the imperfect state of our knowl- 
edge of their properties. 

The method of classification which we will adopt, and which we believe 



CLASSIFICATION OF THE ELEMENTS. 27 

to be more natural than any hitherto suggested, is based upon the chem- 
ical properties of the oxides and upon the valence of the elements. We 
would abandon entirely the division into metals and metalloids, and sub- 
stitute for it a division into four great classes, according to the nature of 
the oxides and the existence or non-existence of oxysalts. In the first of 
these classes hydrogen and oxygen are placed together, for the reason that, 
although they differ from each other in many of their properties, they to- 
gether form the basis of our classification, and may, for this and other 
reasons, be regarded as typical elements. They both play important 
parts in the formation of acids, and neither would find a suitable place in 
either of the other classes. Our primary division would then be as follows: 

Class I. — Typical elements. 

Class II. — Elements whose oxides unite with water to form acids, never 
to form bases. Which do not form oxysalts. 

This class contains all the so-called metalloids except hydrogen and 
oxygen. 

Class III. — Elements whose oxides unite with water, some to form 
bases, others to form acids. Which form oxysalts. 

Class IV. — Elements whose oxides unite with water to form bases ; 
never to form acids. Which form oxysalts. 

In this class are included the more strongly electro-positive metals. 

Within the classes a further subdivision is made into groups, each 
group containing those elements within the class which have equal valen- 
ces, which form corresponding compounds, and whose chemical charac- 
ters are otherwise similar. 



Group I. — Hydrogen. 
Group II. — Oxygen. 



Class I. 



Class II. 



Group I. — Fluorine, chlorine, bromine, iodine. 

Group II. — Sulphur, selenium, tellurium. 

Group III. — Nitrogen, phosphorus, arsenic, antimony. 

Group IV. — Boron. 

Group V. — Carbon, silicon. 

Group "VI. — Vanadium, niobium, tantalium. 

Group VII. — Molybdenum, tungsten, osmium (?). 

Class III. 

Group I. — Gold. 

Group II. — Chromium, manganese, iron. 

Group III. — Aluminium, gallium (?), indium (?), glucinium. 

Group IV. — Uranium. 

Group V. — Lead. 

Group VI. — Bismuth. 

Group VII. — Titanium, zirconium, tin. 

Group VIII. — Palladium, platinum. 

Group IX. — Rhodium, ruthenium, iridium. 



28 GENERAL MEDICAL CHEMISTRY. 

Class IV. 

Group I. — Lithium, sodium, potassium, rubidium, caesium, silver. 

Group II. — Thallium. 

Group III. — Calcium, strontium, barium. 

Group IV. — Magnesium, zinc, cadmium. 

Group V. — Nickel, cobalt. 

Group VI. — Copper, mercury. 

Group VII. — Yttrium, cerium, lanthanium, didymium, erbium. 

Group VIII. — Thorium. 



Physical Characters of Chemical Interest. 

Crystallization. — Solid substances exist in two forms, amorphous 
•and crystalline. In the former they assume no definite geometrical 
shape ; they conduct heat equally well in all directions ; they break 
irregularly; and, if transparent, allow light to pass through them equally 
well in all directions. A solid in the crystalline form has a definite geo- 
metrical shape ; conducts heat more readily in some directions than in 
others; when broken, separates in certain directions, called planes of 
cleavage, more readily than in others; and modifies the course of lumi- 
nous rays passing through it differently when they pass in certain direc- 
tions than when they pass in others. 

Crystals are formed in one of four ways : 1, an amorphous substance, 
by slow and gradual modification, may assume the crystalline form, as 
vitreous arsenic trioxide (q. v.) passes to the crystalline variety. 2, a 
fused solid, on cooling, crystallizes, as bismuth. 3, when a solid is sub- 
limed it is usually condensed in the form of crystals. Such is the case 
with arsenic trioxide. 4, the usual method of obtaining crystals is by 
the evaporation of a solution of the substance. If the evaporation be 
slow and the solution at rest, the crystals are large and well-defined. If 
the crystals separate by the sudden cooling of a hot solution, especially 
if it be agitated during the cooling, they are small. 

Crystallography, treating of the relations of the geometric forms of 
crystals, has become an extended branch 6f science, only the fundamen- 
tal principles and chemical applications of which can be here considered. 

Most crystals may be divided by one or more imaginary planes into 
equal, symmetrical halves; such planes are called planes of symmetry. 
A normal erected upon such a plane and prolonged in both directions 
until it meets opposite parts of the exterior of the crystal, at equal dis- 
tances from the plane of symmetry, is called an axis of symmetry. When 
a plane of symmetry contains two or more equivalent linear directions 
passing through the centre, that plane is the principal plane of symmetry, 
and the axis of symmetry normal to this plane is the principal axis. 

Upon the relations of these imaginary planes and axes a classification 
of all crystalline forms into six systems has been based. These systems 
are the following: 

First. — The regular or cubic system. — In crystals of this system there 
are three equal axes crossing each other at right angles. The simple forms 
are the cube and its derivatives, the octahedron, tetrahedron, and rhombic 
dodecahedron. The crystals expand equally in all directions when heated, 
and are not doubly refracting. 

Second. — The pyramidal, right square prismatic or tetragonal system, 



PHYSICAL CHARACTERS OF CHEMICAL INTEREST. 29 

contains those crystals which have three axes placed at right angles to 
each other — two being equal to each other, and the third either longer or 
shorter. The simple forms are two prisms, in one of which the equal 
axes terminate in the angles of the principal plane, and in the other in 
its sides; and two octahedra, differing from each other in the same way 
as the prisms. The crystals of this system expand equally only in two 
directions when heated; they have but one axis of single refraction, and 
in other directions refract light doubly. 

Tliird. — The hexagonal or rhombohedral system includes crystals hav- 
ing four axes, three of which are of equal length, cross each other at 60°, 
and in the same plane; to which plane the fourth axis, longer or shorter 
than the others, is at right angles. The simple forms are the direct dode- 
cahedron, composed of two hexagonal pyramids base to base, in which 
the equal axes terminate in the angles of the principal plane; the inverse 
dodecahedron, which differs from the direct in that the axes terminate in 
the sides of the principal plane; the rhombohedron; and the six-sided 
prism. The crystals expand equally in two directions when heated; re- 
fract light singly through the principal axis, but in other directions 
refract it doubly. 

Fourth. — The rhombic, right rectangular prismatic, or prismatic sys- 
tem. — The axes of crystals of this system are three in number, all at right 
angles to each other, and differing- in length. Thev, like the two follow- 
ing systems, have no true principal plane or axis. The simple forms ar& 
the right rhombic octahedron and the right prism with a rhombic base. 

Fifth. — The oblique or monosymmetric system. — The crystals of this 
system have three axes, two of which cross each other obliquely and at 
right angles to the third. These axes may be all of unequal length. 
The simple forms are the oblique octahedron with a rhombic base and 
the oblique rhombic prism. 

Sixth. — The asymmetric, anorthic, or doubly oblique sy stein contains 
crystals having three axes of unequal length, crossing each other at an- 
gles not right angles. 

The crystals of the fourth, fifth, and sixth systems, when heated, ex- 
pand equally in the directions of their three axes; they refract light 
doubly except in two axes. 

It sometimes happens that half the faces of a simple crystal are de- 
veloped in the formation of a derivative form at the expense of the other 
half, which are entirely wanting; such a crystal is said to be hemihedralj 
it can be developed only in a system having a principal axis. 

Isomorphism. — Although the number of simple forms of crystals is 
small, the number of their modifications is great; these forms differ from 
each other in the values of the axes and of the angles of the crystals. 

It has been observed that in many instances two or more substances 
crystallize in forms absolutely identical which each other, and, in most 
cases, such substances resemble each other in their chemical constitution ; 
they are said to be isomorphous. This identity of crystalline form does not 
depend so much upon the nature of the elements themselves, as upon the 
structure of the molecule. The protoxide and peroxide of iron do not 
crystallize in the same form, nor can they be substituted for each other 
in reactions without radically altering the properties of the resultant com- 
pound. On the other hand, all that class of salts known as alums (see 
p. 383) are isomorphous; not only are their crystals identical in shape, 
but a crystal of one alum, placed in a saturated solution of another, grows 
by regular deposition of the second upon its surface. Other alums may 



30 GENERAL MEDICAL CHEMISTRY. 

be subsequently added to the crystal, a section of which will then exhibit 
the various salts, layer upon layer. 

Dimorphism. — Although most substances crystallize, if at all, in one 
simple form or in some of its modifications, a few bodies are capable of 
assuming two crystalline forms belonging to different systems; such are 
said to be dimorphous. Thus, sulphur, as obtained by the evaporation of 
its solution in carbon disulphide, forms octahedra belonging to the fourth 
system; when obtained by cooling melted sulphur, the crystals are oblique 
prisms, belonging to the fifth system. Occasional instances of trimor- 
phism, of the formation of crystals belonging to three different systems 
by the same substance, are also known. 

Aelotropy. — Dimorphism apart, a few substances are known to exist in 
more than one solid form. These varieties of the same substance exhibit 
different physical properties, while their chemical qualities are the same 
in kind. Such modifications are said to be allotropic. One or more allo- 
tropic modifications of a substance are crystalline, the other or others 
amorphous or vitreous. Sulphur, for example, exists not only in two di- 
morphous varieties of crystals, but also in a third, allotropic form, in which 
it is flexible, amorphous, and transparent. Carbon exists in three allotro- 
pic forms : two crystalline, the diamond and graphite ; the third amor- 
phous. 

In passing from one allotropic modification to another, a substance 
absorbs or gives out heat. 

Specific Heat. — Equal volumes of different substances at the same 
temperature contain different amounts of heat. If two equal volumes of 
the same liquid of different temperatures be mixed together, the resulting 
mixture has a temperature which is the mean between the temperatures 
of the original volumes. If one litre of water at 4° be mixed with a litre at 
38°, the resulting two litres will have a temperature of 21°. Mixtures of 
equal volumes of different substances at different temperatures do not 
have a temperature which is the mean of the original temperatures of 
its constituents. A litre of water at 4°, mixed with a litre of mercury 
at 38°, forms a mixture whose temperature is 27°. Mercury and water, 
therefor, differ from each other in their capacity for heat. The same 
difference exists in a more marked degree between equal weights of dis- 
similar bodies; if a pound of water at 4° be agitated with a pound of 
mercury at 70°, both liquids will have a temperature of 67°. 

The amount of heat required to raise a kilo of water 1° in tempera- 
ture is a definite quantity. The specific heat of any substance is the 
amount of heat required to raise one kilo of that substance 1° in tempera- 
ture, expressed in terms having the amount of heat required to raise a 
kilo of water 1° as unity. 

Spectroscopy. — Light in passing through a prism is not only refracted 
into a different course, but is also decomposed or dispersed into different 
colors, which make up a spectrum. A spectrum is one of three kinds: 
1st, continuous, consisting of a continuous band of colors: red, orange, 
yellow, green, blue, indigo, and violet. Such spectra are produced by 
light from white-hot solids and liquids, from gas-light, candle-light, lime- 
light, and electric light. 2d, bright-line spectra, composed of bright 
lines upon a dark ground, are produced by glowing vapors and gases. 
3d, absorption spectra consist of continuous spectra crossed by dark lines 
or bands, and are produced by light which gives a continuous spectrum 
passing through a solid, liquid, or gas capable of absorbing rays of certain 
colors. 



PHYSICAL CHARACTERS OF CHEMICAL INTEREST. 81 

The solar spectrum belongs to the third class. Fraunhofer was the 
first to observe that the spectrum of sunlight was not continuous, but in- 
terrupted by a great number of black lines, crossing it throughout its 
length. The more prominent of these lines he designated by the letters 
A, B, C, D, E, F, G, H, a, and b. Most of these lines correspond in po- 
sition with the bright lines produced by the incandescent vapors of vari- 
ous elements. 

The spectroscope consists of four essential parts : 1st, the slit, a 
linear opening between two accurately straight and parallel knife-edges ; 
2d, the collimating lens, a biconvex lens in whose principal focus the 
slit is placed, and whose object it is to render the rays from the slit 
parallel before they enter the prism ; 3d, the prism of dense glass, 
and usually of 60°, so placed that its refracting edge is parallel to the slit; 
4th, an observing telescope, so arranged as to receive the rays as they 
emerge from the prism. In direct vision spectroscopes a compound 
prism is used, so made up of prisms of different kinds of glass that the 
emerging ray is in the same straight line as the entering ray. 

As the spectra produced by different substances are characterized by 
the positions of the lines or bands, some means of fixing their location 
is required. The usual method consists in determining their relation to 
the principal Fraunhofer lines. As, however, the relative positions of 
these lines vary with the nature of the substance of which the prism is 
made, although their position with regard to the color of the spectrum is 
fixed, no two of the arbitrary scales used will give the same reading. 

The most satisfactory method of stating the positions of lines and 
bands is in wave-lengths. The lengths of the waves of rays of different 
degrees of refrangibility have been carefully determined, the unit of 
measurement being the tenth-metre, of which 10 10 make a metre. The 
wave-lengths, =-X y of the principal Fraunhofer lines, are: 

A 7604.00 D 5892.12 G 4307.25 

B 6867.00 E 5269.13 H, 3968.01 

C 6562.01 F 4860.72 H 2 3933.00 

a 7185.0 b 5172.0 

The scale of wave-lengths can easily be used with any spectroscope 
having an arbitrary scale, with the aid of a curve constructed by interpo- 
lation. To construct such a curve paper is used which is ruled into square 
inches and tenths. The ordinates are marked with a scale of wave- 
lengths and the abscisses with the arbitrary scale of the instrument. The 
position of each principal Fraunhofer line is then carefully determined in 
terms of the arbitrary scale, and marked upon the paper with a X at the 
point where the line of its wave-length and that of its position in the ar- 
bitrary scale cross each other. Through these X a curve is then drawn 
as regularly as possible. In noting the position of an absorption-band the 
position of its centre in the arbitrary scale is observed, and its value in 
wave-lengths obtained from the curve, which, of course, can only be 
used with the scale and prism for which it has been made. 

Polarimetry. — -A ray of light passing from one medium into another 
of different density, at an angle other than 90° to the plane of sepa- 
ration of the two media, is deflected from its course, or refracted. Cer- 
tain substances have the power, not only of deflecting a ray falling 
upon them in certain directions, but also of dividing it into two rays, 
which are peculiarly modified. The splitting of the ray is termed double 



32 GENERAL MEDICAL CHEMISTRY. 

refraction, and the altered rays are said to be polarized. When a ray of 
such polarized light meets a mirror held at a certain angle, or a crystal of 
Iceland spar peculiarly cut (a Nichols' prism), also at a certain angle, it 
is extinguished. The crystal which produces the polarization is called 
the polarizer, and that which produces the extinction the analyzer. 

If, when the polarizer and analyzer are so adjusted as to extinguish a 
~*ay passing through the former, certain substances are brought between 
them, light again passes through the analyzer; and in order again to pro- 
duce extinction, the analyzer must be rotated upon the axis of the ray to the 
right or to the left. Substances capable of thus influencing polarized light 
are said to be optically active. If, to produce extinction, the analyzer is 
turned in the direction of the hands of a watch, the substance is said to 
be dextrogyrouSy if in the opposite direction, Icevogyrous. 

The distance through which the analyzer must be turned depends upon 
the peculiar power of the optically active substance, the length of the 
column interposed, the concentration if in solution, and the wave-length 
of the original ray of light. The specific rotary power of a substance is 
the rotation produced, in degrees and tenths, by one gram of the sub- 
stance dissolved in one cubic centimetre of a non-active solvent, and ex- 
amined in a column one decimetre long. The specific rotary power is de- 
termined by dissolving a known weight of the substance in a given volume 
of solvent, and observing the angle of rotation produced by a column of 
given length. Then let jt> = weight in grams of the substance contained 
in 1 c.c. of solution; I the length of the column in decimetres; a the an- 
gle of rotation observed; and [a] the specific rotary power sought, we 
have 

a 

p 1 

In most instruments monochromatic light, corresponding to the D line of 
the solar spectrum, is used, and the specific rotary power for that ray is 
expressed by the sign [a\ D . The fact that the rotation is right-handed is 
expressed by the sign +, and that it is left-handed by the sign — . 

It will be seen from the above formula that, knowing the value of [#] D 
for any given substance, we can determine the weight of that substance 
in a solution by the formula 

a 

p= . 

[a]j>xl 






Part % 

SPECIAL CHEMISTRY. 



CLASS I. 



TYPICAL ELEMENTS. 

Hydrogen H 1 

Oxygen O 16 

Although, in a strict sense, hydrogen is regarded by most chemists as 
the one and only type-element — that whose atom is the unit of atomic 
and molecular weights — the important part which oxygen plays in the 
formation of those compounds whose nature forms the basis of our clas- 
sification, its acid-forming power in organic compounds, and the differ- 
ences existing between its properties and those of the elements of the 
sulphur group, with which it is usually classed, warrant us in separating 
it from the other elements and elevating it to the position it here occu- 
pies. 

HYDROGEN. 
H 1 



Hydrogen exists uncombined in the gases from the fumaroles of Ice- 
land and Tuscany; in combination very abundantly in water, in many 
organic substances, and in ammoniacal compounds. 

Hydrogen is liberated from its compounds: 

First. — By the decomposition of acidulated water by the galvanic 
current, when it is given off from the negative pole. This method is re 
sorted to when chemically pure hydrogen is required. 

Second. — By the decomposition of water by the chemical action of 
certain metals. This takes place either at ordinary temperatures, as in 
the case of sodium — 

Na 2 +2H a O:=2NaHO + H 2 , 
or at a red heat, as in the case of iron — 

3Fe 2 + 8H 2 = 2Fe 3 4 + 8H 2 . 



34 GENERAL MEDICAL CHEMISTRY. 

Third. — By the decomposing action exerted by certain metals, such 
as zinc, upon the mineral acids in the presence of water — 

Zn + S0 4 H 2 + xH 2 = S0 4 Zn + H 2 + xH a O. 

What part the water plays in the reaction is still a subject of discus- 
sion ; it is probable that its action is rather physical than chemical. 
Chemically pure zinc, or zinc whose surface has been coated with an 
alloy of zinc and mercury, does not decompose the acid unless it forms 
part of a galvanic battery whose circuit is closed. The zincs of galvanic 
batteries are therefor coated with the alloy mentioned — are amalgam- 
ated — to prevent waste of zinc and acid. 

This method is the one resorted to for obtaining hydrogen in the 
laboratory ; the gas so obtained is, however, contaminated with small 
quantities of other gases, hydrogen phosphide, sulphide, and arsenide. 

At ordinary temperatures and pressure, and when pure, it is a colorless, 
odorless, tasteless gas, fourteen and one-half times lighter than air, being 
the lightest known substance. One litre at 0° and 760 mm. barometric pres- 
sure weighs 0.0896 gram, a quantity which forms an important unit of 
weight, called by Hofmann a crith (KpiOr] = a barley-corn). It is almost in- 
soluble in water and in alcohol. It is a better conductor of heat and elec- 
tricity than is any other gas. It is the most diffusible of gases, in obedi- 
ence to the law that the diffusion volume of a gas is in inverse proportion 
to the square root of its density. The rapidity with which its diffusion 
takes place renders the use of hydrogen, which has been kept for even a 
comparatively short time in metallic gasometers, dangerous from the 
formation of explosive mixtures of air and hydrogen within. India-rub- 
ber gas-bags are more dangerous than metallic gasometers. 

Hydrogen was formerly supposed to be a permanent gas, i. e., not 
capable of reduction to the liquid or solid state. Recently, however, 
Cailletet, of Paris, obtained it in the form of a visible cloud ; and Pictet, 
of Geneva, with a pressure of 650 atmospheres and a temperature of 
— 140°, succeeded in reducing it to a steel-blue liquid. 

Under ordinary conditions hydrogen exhibits no great tendency to 
unite with other elements, chlorine being the only one with which it will 
unite at ordinary temperatures, and that only under the influence of 
light. At higher temperatures it unites with oxygen. 

Mixtures of hydrogen and oxygen remain such indefinitely at ordinary 
temperatures, but if heated sufficiently even at a single point, as by the 
passage of an electric spark, a sudden and complete union takes place 
throughout the mass (if the proportions be H2 to 01), attended by a vio- 
lent explosion, due to the formation of vapor of water and its sudden ex- 
pansion under the influence of the intense heat produced by the union. 
Hydrogen has so marked a tendency to unite with oxygen at high tem- 
peratures that many compounds containing oxygen give up that element 
when heated in an atmosphere of hydrogen : 

CuO + H 2 = Cu + H 2 0. 

Cupric oxide. Hydrogen. Copper. Water. 

This removal of oxygen from a compound is called a reduction or de- 
oxidation, and it is by such a process that the reduced iron, or iron by 
hydrogen of pharmacy, is prepared. 

At the instant that hydrogen is liberated from its compounds it has a 
deoxidizing power similar to that which ordinary hydrogen possesses only 



OXYGEN. 35 

at elevated temperatures. The greater energy of hydrogen, and of other 
elements as well, in this nascent state, may be thus explained : free hydro- 
gen exists in the form of molecules, each one of which is composed of two 
atoms. At the instant of its liberation from a compound, on the other 
hand, it is in the form of individual atoms, and that portion of force re- 
quired to split up the molecule into atoms, necessary when free hydrogen 
enters into reaction, is not required when the gas is in the nascent state, 
and consequently a less addition of force in the shape of heat is required 
to bring about the reaction. 

Hydrogen burns in air with a pale but hot flame, the product of the 
combustion being water. It does not maintain combustion or respiration; a 
lighted taper is extinguished when immersed in an atmosphere of hydro- 
gen, and under like conditions an animal dies — not from any poisonous 
action of the gas, but from its inability to maintain the processes of res- 
piration. 

In its physical and chemical properties, this element more closely re- 
sembles those usually ranked as metals than it does those forming the class 
of metalloids, among which it is usually placed; its conducting power, its 
appearance in the liquid form, as well as its relation to the acids, which 
may be considered as salts of hydrogen, tend to separate it from the 
metalloids. 

Hydrogen is constantly found in small quantity in the gases exhaled 
from the lungs, as well as in those contained in the stomach and intestines. 



OXYGEN. 
O 16 

Oxygen is the most abundant of the elements, and exists uncombined 
in atmospheric air, of which it forms 21 per cent. It also enters into the 
composition of a vast number of compound substances, mineral, vege- 
table, and animal. 

Although existing in air, and only mixed with nitrogen and small quan- 
tities of other gases, no process has yet been devised which can be advan- 
tageously used for obtaining oxygen from this source directly. Resource 
is always had to the decomposition of some substance rich in oxygen. 

First. — By heating mercuric oxide (the red oxide) it is decomposed 
into mercury and oxygen: 

2HgO=2Hg+O a . 

This process is only of historical interest, as being the one by which 
Priestley first obtained oxygen in 1774. 

Second. — By heating manganese dioxide (black oxide of manganese) to 
redness in an iron or clay retort: 

3Mn0 2 =Mn 3 4 + 2 . 

The yield according to this equation should be 85 litres of oxygen 
from 1 kilo of the oxide; but, owing to impurities, the amount is much less 
and the gas is impure. 

Third. — By heating manganese dioxide with sulphuric acid in a glass 
flask: 

2Mn0 2 + 2S0 4 H 2 =2S0 4 Mn + 2H a + 2 . 



36 GENERAL MEDICAL CHEMISTRY. 

The theoretical yield is 128 litres of gas from each kilo of oxide. 
Fourth. — The best method, and that generally used, is by the decom- 
position of potassium chlorate by heat: 

2C10 3 K=2KCl+30 a . 

The chlorate yields up all of its oxygen to the amount of 272.6 litres 
per kilo of chlorate. 

The evolution of gas takes place at a lower temperature and much 
more quietly if the chlorate be mixed with one to two parts by weight of man- 
ganese dioxide. At the end of the operation the manganese dioxide re- 
mains apparently unaltered, and it is probable that during the action it 
goes through a series of oscillating oxidations and deoxidations, which 
take place at a lower temperature than that required for the decomposition 
of the chlorate alone. 

Methods have been suggested by Tessie du Motay, Boussingault, and 
Mallet, for extracting oxygen from the air, and attempts have been made 
to utilize these processes in the arts; but the chlorate process is still in 
general use, on account of its comparative cheapness and the purity of the 
product. 

Oxygen is a colorless, odorless, tasteless gas; liquefies under the com- 
bined influence of a pressure of 300 atmospheres and a temperature of 
— 140° (Pictet). The specific gravity of the gas is 1.10563 A,* or 15.95 
H,f and that of the liquid 0.9787 (Pictet); 1 litre of the gas at 0° C. 
and 760 mm. weighs 1.437 gram. It is very sparingly soluble in water, 
somewhat more soluble in absolute alcohol. 

Oxygen is characterized, chemically, by the strong tendency which 
it exhibits to enter into combination with other elements, only one of 
which is known, i. e. } fluorine, that does not form an oxygenated com- 
pound. With most elements it is capable of uniting directly, especially 
at elevated temperatures. In many instances this union is attended by the 
appearance of light, and always by the extrication of heat. The lumi- 
nous union of oxygen with another element constitutes the familiar phe- 
nomenon of combustion, and is the principal source from which we obtain 
heat and light. A body is said to be combustible when it is capable of 
so energetically combining with oxygen as to liberate light as well as 
heat. Certain gases are said to be supporters of combustion, because 
combustible substances will unite with them or with some of their con- 
stituents, the union being attended with the appearance of heat and 
light. The distinction between combustible substances and supporters 
of combustion is, however, one of mere convenience; the action taking 
place between the two substances, one is as much a party to it as the 
other. 

A jet of air burns in an atmosphere of coal-gas as readily, and with 
the same luminous flame which is observed when a jet of coal-gas is 
caused to burn in air. 

Oxidations, and indeed, most chemical wiions, are attended with a 
liberation of heat; and in some instances, as when powdered antimony is 
thrown into an atmosphere of chlorine, light is also observed without the 
occurrence of any oxidation. 

The process of respiration is very similar to combustion, and as oxy- 
gen gas is the best supporter of combustion, so, in the diluted form in 

* Air unity. f Hydrogen-unity. 



COMPOUNDS OF HYDROGEN AND OXYGEN. 37 

which it exists in atmospheric air, it is not only the best, but the only- 
supporter of animal respiration. 



Ozone. 

Air through which discharges of static electricity have passed as- 
sumes a peculiar odor, resembling somewhat that of sulphur; the same 
odor is perceived in the oxygen obtained by the decomposition of water 
if the electrodes be of platinum or gold. This odor is due to the conver- 
sion of a part of the oxygen into an allotropic modification called ozone. 

Ozone has not been obtained free from oxygen; indeed, the highest 
degree of concentration which has been reached does not exceed one per 
cent, of ozone. Thus diluted, ozone is produced: 1st, by the decom- 
position of water by the battery; 2d, by the slow oxidation of phos- 
phorus in damp air; 3d, by the action of concentrated sulphuric acid 
upon barium dioxide; 4th, by the passage of electric discharges through 
air or oxygen. It is by the last method that ozonized oxygen is usu- 
ally obtained artificially, and that the traces of ozone existing in the 
atmosphere are produced. 

Ozone is condensed oxygen, as is shown, by the fact that the latter 
gas contracts when ozonized. When heated to 100° it begins to revert to 
its primitive form of oxygen, a change which is complete at 237°. It is 
a powerful oxidizing agent; it converts iodides into iodates; it is de- 
stroyed by contact with rubber, cork, and other organic materials, which 
it oxidizes; it decolorizes organic pigments. 

The presence of ozone in air is demonstrated by its action upon a 
paper impregnated with a mixture of starch and potassium iodide, which 
turns blue on contact with ozone. To exclude other gases capable of 
bluing such paper, a faintly red litmus paper, impregnated with potas- 
sium iodide to half its extent, is also used; if the bluing of the starch 
paper be due to ozone, the litmus paper is also blued, and the action upon 
either paper does not take place after the ozonized air has been heated 
to 260°. 

When inhaled, air containing 0.07 gram of ozone per litre causes in- 
tense coryza and haemoptysis. Its presence in atmospheric air has been 
considered by some as favoring, and by others as preventive of, conta- 
gious diseases ; certain it is that, by its oxidizing action, ozone is fatal to 
the lower forms of animal and vegetable life. 



Compounds of Hydrogen and Oxygen. 

Two of these are known: 

First. — Hydrogen oxide, or water. 

Second. — Hydrogen peroxide, or oxygenated water. 

Water— H 2 0. 

Occurrence. — Water exists, widely disseminated and in large quantities, 
in the three kingdoms of nature, in the three forms of solid, liquid, and 
gas. 

In unorganized nature, water occurs in the gaseous form in atmos- 
pheric air (see p. 96), and in the vapors discharged from the earth in 
volcanic regions. In the liquid form it exists very abundantly, hold- 



38 GENERAL MEDICAL CHEMISTRY. 

ing in solution solid and gaseous matter in varying quantities. In the 
solid form, as ice, at temperatures below 0° C, and also in the form of 
loater of crystallization, by which is understood a certain definite quan- 
tity of water taken up by many substances when they assume the crys- 
talline form. This water is not in the liquid form at ordinary tempera- 
tures, nor yet in the form of ice, but combined with the solid matter of 
the crystal. Although the chemical nature of the substance is not modi- 
fied by the presence or absence of water of crystallization, its presence is 
necessary to the maintenance of the peculiar shape of the crystal. The 
tenacity with which water of crystallization is held in combination varies 
in different substances; in some the union is so loose that on exposure 
to air the crystal loses its water and falls to a shapeless powder; it is then 
said to effloresce. Other crystals, which are said to be permanent in air, 
only lose their water of crystallization if heated; they then melt, and 
part or all the water is driven off, leaving a shapeless mass, which is 
capable of crystallization only when the proper amount of water is again 
taken up. 

In the organized world, water forms a constituent part of every fluid 
and tissue (see p. 67). 

Formation. — Water is produced in a great number of chemical re- 
actions. 

First. — Most simply by the direct union of its constituent gases, 
brought about by elevation of temperature: 

2H 2 + 2 =2H 2 0. 

In obedience to Avogadro's law, the volume of water-gas formed is to 
the volume of the mixture before union as 2 : 3, provided the mixture 
originally contained two volumes of hydrogen to one volume of oxygen. 

Second. — Whenever hydrogen, or a substance containing hydrogen, is 
burned in air or oxygen. 

Third. — When an organic substance containing hydrogen is heated to 
redness in the presence of cupric oxide, or of other substances capable of 
yielding oxygen — 

C 2 H 6 + 6CuO = 6Cu + 2C0 2 +3H 2 0, 

Alcohol. Cupric Copper. Carbon Water, 
oxide. dioxide. 

a reaction which is utilized for the determination of the amount of 
hydrogen contained in organic substances. 

Fourth. — When an acid and a hydrate react upon each other to form 
a salt : 

S0 4 H 2 + 2KHO = S0 4 K 2 + 2H 2 0. 

Sulphuric Potassium Potassium Water, 
acid. hydrate. sulphate. 

Fifth. — In the reduction of metallic oxides by hydrogen : 
CnO + H 2 = Cu + H 2 0. 

Cupric Hydrogen. Copper. Water, 

oxide. 

Sixth. — In the reduction and oxidation of a number of organic sub- 
stances. 



COMPOUNDS OF HYDROGEN AND OXYGEN. 39 

Pure water may be obtained either by the union of its elements or 
by the separation of naturally occurring water from the solid and gaseous 
substances which it holds in solution and in suspension. The purification 
of natural water, effected by the processes of filtration and distillation, is 
the method resorted to in all cases. To obtain water sufficiently pure 
for chemical purposes, it is boiled in a vessel of tinned copper, called a 
still, and the vapor is directed through a tube, around which cold water 
is made to circulate, and in which the vapor is condensed to the liquid 
form. The condensing tube is usually of block-tin, or, preferably, of glass. 
The first 10 per cent, of condensed water is rejected, as it contains air, 
carbon dioxide, ammonia, and many volatile substances which the water 
may have held in solution. The following 70 per cent, of the original 
volume is collected for use, the distillation being stopped while 20 per 
cent, of the original water remains in the still. 

Distilled water so obtained should be perfectly clear, colorless, odor- 
less, and tasteless, and should leave no residue when a small quantity is 
evaporated upon platinum foil. Although ordinary distilled water is 
sufficiently pure for most chemical purposes, it is not absolutely free 
from impurity, and when evaporated in a platinum basin it leaves more 
or less residue. To obtain a chemically pure water is a matter of some 
difficulty. Distilled water should be used in the preparation of all aque- 
ous solutions intended for use in chemical manipulations. 

Physical 'properties. — At temperatures below 0° C, with a barometric 
pressure of 760 mm., water assumes the solid form ; between 0° and 100° 
it is liquid ; and at temperatures above 100°, the pressure remaining the 
same, it is gaseous. The freezing and boiling points are modified by the 
barometric pressure, and by the presence of solid matter in solution in 
water. The freezing-point is, under ordinary conditions, at 0° of the 
Centigrade scale, and at 32° of the Fahrenheit. Under certain conditions, 
as when enclosed in capillary tubes and at complete rest, it may be cooled 
as far as — 15° C. without solidifying. If water so cooled be agitated, it 
solidifies instantly, and the temperature suddenly rises to 0°. 

In solidifying, water is rather suddenly expanded, and this expansion 
takes place with great force; for this reason ice is lighter than water at 
any temperature below 8.5°, and consequently floats. Water is at its 
densest at 4° C. The solidification of water is a crystallization; the form 
of the crystals, which belong to the hexagonal system, may be readily 
observed in snow, or even, under suitable conditions, in ice, which is com- 
posed of closely applied crystals. 

The boiling-point is subject to much greater variations than the freez- 
ing-point; it falls, with diminutions of pressure, to the extent of about 
1° C. for each fall of 25 mm. of pressure. Conversely, as the pressure is 
increased the boiling-point rises, attaining 200° with a pressure of be- 
tween fifteen and sixteen atmospheres. Advantage is taken of the fall 
of the boiling-point with diminished pressure to measure the altitude of 
mountains, upon the tops of some of the higher of which boiling water 
is not hot enough to be of service in culinary operations. The increased 
temperature which may be imparted to liquid water under pressure is 
utilized in many processes in the laboratory and in the arts, for effecting 
solutions and chemical actions which do not take place at lower temper- 
atures. The boiling-point of water holding solid matter in solution is 
higher than that of pure water, the degree of increase depending upon 
the amount and nature of the substance dissolved. On the other hand, 
mixtures of water with liquids of lower boiling-point boil at tempera- 



40 GENERAL MEDICAL CHEMISTRY. 

tures less than 100°. Although the conversion of water into water-gas 
takes place most actively at 100°, water and ice evaporate at all tem- 
peratures. 

One of the most important physical properties of water is its high 
rank as a solvent, there being comparatively few substances, solid, liquid, 
or gaseous, which are absolutely insoluble in it. The solution of a sub- 
stance in water may take place in two very different ways. The action 
may be partly chemical, as when barium oxide is dissolved in water, com- 
bination of the two substances taking place with formation of barium 
hydrate — 

BaO+H 2 0=BaH 2 2 , 

which is subsequently dissolved. In solutions of this kind, as in other 
instances where chemical union takes place, the action is accompanied by 
an increase of temperature. In true simple solutions, on the other hand, 
as when common salt is dissolved in water, there is no chemical action; 
no increase, but, on the contrary, a diminution of temperature. 

The quantity of a substance which a given volume of water is capable 
of dissolving depends upon the nature of the substance, the temperature, 
the presence or absence of other substances already in solution, and the pres- 
ence or absence of another solvent. Some substances are much more soluble 
in water than others; barium sulphate is insoluble in water, while calcium 
chloride has such an avidity for the solvent that, when exposed to the air, it 
quickly absorbs sufficient water therefrom to form a solution. That pas- 
sage of a solid into solution in absorbed water is known as deliquescence. 
As a rule, the power of water to dissolve solids increases with the tem- 
perature, while the solubility of gases in water is greater at low than at 
high temperatures. The quantity of any substance which a given volume 
of water will dissolve at a given temperature is definite; and when this 
quantity has been dissolved, the solution is said to be saturated / it is 
only so for that degree of temperature at which it has been made. Sat- 
urated solutions of solids, as a rule, can be made to dissolve further quan- 
tities by elevation of temperature, or to deposit that which they already 
hold by cooling. Saturated solutions of gases are modified by variations 
of temperature in the opposite way. In the cases of certain salts, solu- 
tions saturated at high temperatures may be cooled without depositing 
any of the salt; they thus become at lower temperatures supersaturated 
solutions; containing more of the salt than they could be made to dis- 
solve at the temperature to which they have been cooled. A saturated 
solution of one substance in water is often capable of dissolving consid- 
erable quantities of another substance, and of then becoming capable of 
taking up a further quantity of the first substance. The power of water 
to dissolve gases increases with increased pressure. Fats, resins, and, in 
general, organic substances containing a large number of carbon atoms, 
are insoluble in water. 

Vapor of water is colorless, transparent, invisible (the white cloud, 
usually called steam, is produced by the condensation of vapor of water 
into minute liquid drops); its specific gravity is 0.6234A = 1 or 18 — 11=2. 
A litre of vapor of water weighs (reduced to 0° and 760 mm.) 0.8064, or 
nine times as much as an equal volume of hydrogen. 

The latent heat of vaporization of water is 536.5 ; that is, as much 
heat is required to vaporize 1 kilo of water at 100° as would raise 536.5 
kilos 1° C. in temperature. In passing from the liquid to the gaseous 
form, water expands 1,696 times in volume. 



COMPOUNDS OF HYDKOGEN AND OXYGEN. 41 

Chemical properties — Decompositions. — First. — By passing the cur- 
rent of a galvanic battery through acidulated water, two volumes of hy- 
drogen are given off at the zinc or negative pole, and one volume of 
oxygen at the platinum or positive pole. 

Second. — By passing vapor of water through a platinum tube heated 
to whiteness, or through a porous porcelain tube heated to about 1,100° 
(Deville). 

Third. — By acting upon water at low temperatures with the alkaline 
metals, hydrogen is given off, and a hydrate of the metal remains in solu- 
tion in the excess of water: 

2H 2 + 2K = 2KHO + H 8 . 

Water. Potassium. Potassium Hydrogen, 
hydrate. 

Fourth. — By passing vapor of water over iron heated to redness, an 
oxide of the metal is formed and hydrogen liberated (see p. 33). 

Other reactions. — First. — Water combines with many metallic oxides to 
form compounds known as hydrates, which may be considered as molecules 
of water in which one-half the hydrogen has been replaced by an equivalent 
quantity of the metal. When the metal is univalent, the action takes 
place between single molecules of oxide and water, with the formation of 
two molecules of hydrate; or, in other words, the hydrate is formed by the 
substitution of an atom of metal for one atom of hydrogen in a single 
molecule of water: 



K 2 -f H 2 = 2KHO; 
!}0 + H}0=*(i|0) 

Potassium Water. Potassium 

oxide. hydrate. 

When the metal is divalent, the action still takes place between single 
molecules of water and oxide, but with the formation of a single molecule 
of hydrate; or, in other words, the hydrate is formed by the substitution 
of an atom of the divalent metal for a double atom of hydrogen in a 
double molecule of water: 

CaO + H 2 = CaH 2 2 ; 
or, 



°4:k 

Calcium Water. Calcium 

oxide. hydrate. 



Ca ) . H ) 

O \ + n) 



Second. — Water combines also with the oxides of those elements usu- 
ally classed as metalloids, with the formation of hydrates which differ 
very materially in their chemical properties from the hydrates of the 
metals. It combines with the oxides of sulphur and phosphorus to form 
the acids of those elements: 



S0 3 + H 2 = 


= S0 4 H 2 


PA + 3H 2 ° = 


= 2P0 4 H 3 . 


Sulphur Water, 
trioxide. 


Sulphuric 
acid. 


Phosphorus Water, 
pentoxide. 


Phosphoric 
acid. 



42 GENERAL MEDICAL CHEMISTRY. 

Certain of these acids are capable of combining" chemically with a greater 
number of molecules of water to form what are known as hydrates of the 
acids. Thus, there are definite hydrates of sulphuric acid having the for- 
mulas— 

S0 4 H 2 , H 2 and S0 4 H 2 , 2H 2 0, 

which differ materially in their physical properties from the acid S0 4 H 2 . 
That these hydrates are not mere mechanical mixtures is shown by the 
fact that their formation is attended by the liberation of heat. 

Third. — Certain substances exhibit a great tendency to absorb water 
from surrounding 1 bodies, and are therefor used as drying agents; cal- 
cium chloride, sulphuric acid and phosphorus pentoxide are used for 
drying gases in the laboratory. The preservative action of alcohol upon 
animal substances is largely, if not entirely, due to its power of absorbing* 
water, and thus, in a manner, drying the putrescible substances. 

Fourth. — The chlorides of the elements of the third and fourth classes 
are either insoluble in water, or soluble without decomposition; the corre- 
sponding compounds of the second class are decomposed when brought 
into contact with water: 

PC1 3 + 3H 2 = P0 3 H 3 + 3HC1. 

Phosphorus Water. Phosphorous Hydrochloric 
trichloride. acid. acid. 



Natural Waters. 

From whatever source natural water is obtained, it always holds solid 
and gaseous matter in solution, and very frequently solid matter in sus- 
pension as well. The amount and nature of the substances held in solu- 
tion vary greatly with the purity and temperature of the atmosphere 
through which the water has fallen as rain, with the nature of the geo- 
logical strata through or over which it has passed, and with the geo- 
graphical position of the source from which it is obtained. 

Natural waters may be divided into potable and unpotable waters. 
To the first class belong: 1st, rain-water; 2d, snow- and ice-water; 3d r 
spring-water (fresh); 4th, river-water; 5th, lake-water; 6th, well-water. 
To the second belong: 1st, stagnant waters; 2d, sea-water; 3d, mineral- 
spring waters. 

First. — Rain-water varies much in purity according to the locali- 
ties in which it is collected and the condition of the atmosphere at the 
time. It holds in solution comparatively small quantities of solid matter, 
consisting of chlorides, sulphates, and nitrates of sodium and ammonium. 
The amount of hydrochloric acid is greatest in the neighborhood of salt 
water, while the sulphate and nitrate of ammonium are most abundant 
in the rain-water collected in cities. 

The following table of analyses, by Dr. R. Angus Smith, indicates 
variations in the quantity of solid matter in rain-water from different 
localities: 



NATURAL WATERS. 



43 



Rain- Water. — Average Impurities per Million Parts. 



Where collected. 



Ireland, Valencia 

Scotland, five sea-coast country 
places west 

Scotland, eight sea-coast country 
places east 

Scotland, twelve inland country 
places 

England, twelve inland country 
places 

Scotland, six towns (Glasgow ex- 
cluded) 

Darmstadt 

London 

England, six manufacturing towns 

Manchester 

Glasgow. 



8S 



48.67 

12.28 

12.91 

3.38 

3.99 

5.86 
.97 
1.25 
8.70 
5.83 
8.97 



2.73 

3.61 

7.66 

2.06 

5.52 

16.50 
29.17 
20.49 
34.27 
44.82 
70.19 



Sulphuric acid 
for 100 hydro- 
chloric. 


Free acids calcu- 
lated as sul- 
phuric acid. 


s 

2 

2 
<5 


Albuminoid am- 
monia. 


6 


none. 


.18 


.03 


29 


.14 


.48 


.11 


59 


2.44 


.99 


.11 


61 


.31 


.53 


.04 


138 


none. 


1.07 


.11 


282 


3.16 


3.82 


.21 


2998 


1.74 






1645 


3.10 


3.45 


.21 


394 


8.40 


4.99 


.21 


768 


10.17 


5.96 


.25 


782 


15.13 


9.10 


.30 



o 55 

Is 



.37 

.37 
.47 
.31 
.75 
1.16 

"84 

.85 

l.oi 

2.44 



In commenting upon these results, Dr. Smith observes that the 
amount of chlorides is dependent upon the distance from the sea and the 
direction of the prevailing 1 winds; that the sulphuric acid increases as we 
go inland, and is derived partially from the combustion of coal, and par- 
tially from the decomposition of organic matter; and that when the pro- 
portion of sulphuric acid to hydrochloric acid is greater than 11.6 to 100. 
the presence of the excess of the former is due to terrestrial contamination, 

The presence of nitrate and nitrite of ammonium is due, to a certain 
extent, to the decomposition of organic matter, but principally to the 
combustion of coal, as is shown by the large quantity existing in the 
rain-water collected in manufacturing towns, and by the greater propor- 
tion of ammonia found in rain-water in Lyons, by Bineau, in winter than 
in summer: 



Winter. 


Spring. 


Summer. 


Autumn. 


Average 


16.3 


12.1 


3.1. 


4.0 


6.8 



As, during its formation in and passage through the atmosphere, rain- 
water exposes a large surface, it dissolves, besides solids and vapors, 
comparatively large quantities of gases — oxygen, nitrogen, carbon diox- 
ide, and, over cities, sometimes hydrogen sulphide and sulphur dioxide 
— the last-named gases being produced by the combustion of coal con- 
taining sulphides. According to Peligot, a litre of rain-water at Paris 
contains 2.4 c.c. carbon dioxide, 6.59 c.c. oxygen, and 14.0 nitrogen. Ac- 
cording to Gerardin, rain-water at the same place contains from 5.18 c.c. 
to 8. c.c. of oxygen per litre. Great care should be taken, in the collec- 
tion of rain-water, that it should not be allowed to come into contact 
with lead surfaces, as the comparatively small quantities of carbon diox- 
ide and carbonates, and the comparatively large quantities of oxygen and 
nitrates which it contains, render it peculiarly prone to contamination 
with that metal (see p. 56). 



44 GENERAL MEDICAL CHEMISTRY. 

Rain-water is liable to contain notable quantities of organic matter, 
especially in summer, in the shape of vegetable spores, which it holds in 
suspension; the presence of these bodies renders the water liable to be- 
come stale when kept. 

Second — Melted snow and ice. — The waters obtained from these two 
sources differ much from each other as to their purity. That obtained 
from ice is of great purity, so far as dissolved matters go; for these, dur- 
ing crystallization, are to a great extent, although not completely, separa- 
ted from the ice and retained in the unfrozen water. Hassall states that 
in freezing a small portion of water the following separation took place: 

Original , Remaining 

water. e " water. 

Total solids 27.0 3.0 14.2 

Chlorine 1.94 0.9 

Lime 10.53 trace 14.11 

Water obtained by melting the ice of sea-water is used for drinking- 
water in the Arctic regions. Owing, however, to the separation of the 
dissolved gases together with the solids, ice-water has a flat taste. 

The water obtained from melted snow contains about the same pro- 
portion of fixed solid matter as rain-water, but a less proportion of ammo- 
niacal salts and of gases: 





Sodium 
chloride. 


Ammonium 
bicarbonate. 


Ammonium 
nitrate. 


Snow-water 


0.01704 


0.00129 


0.00145 






0.00087 


0.00189 




Sodium 
sulphate. 


Calcium 
sulphate. 


Organic 
matter. 


Snow-water 


0.01563 


0.00088 


0.02385 


Rain-water 


0.01007 


0.00087 


0.02486 


high, mountainous 


regions, the 


drinking-waters 


used are 1 



In high, mountainous regions, the drinking-waters used are largely 
mixtures of melted ice and snow, and many observers have attributed 
the goitre and cretinism prevailing in these locations to the use of such 
water (see p. 50). 

Third. — Spring-water is simply rain-water which has percolated 
through the subjacent strata, and, owing to the conformation of the 
ground and the arrangement of the strata, has made its appearance upon 
the surface at some level below that upon which it originally fell. Dur- 
ing its passage through the earth, in which it is frequently subjected to 
pressure, it dissolves solid and gaseous matter, varying in kind and in 
quantity with the nature of the strata with which the water has been in 
contact, the duration of such contact, and the pressure to which it is 
subjected. 

The amount of extraneous matter dissolved in spring-water, therefor, 
varies greatly — from the water of some saline springs, which are almost 
saturated solutions of sodium chloride, to the pure spring-water which 
flows from the side of a porphyritic or quartz mountain. Between these 
extremes are waters of all degrees of purity. 

Spring-waters from igneous rocks and from the older sedimentary 
formations are sweet, and any spring-water may be so considered whose 
temperature is below 20° and which does not contain more than 0.4 



NATURAL WATERS. 



45 



gram of solid matter in the litre; provided, however, that a large propor- 
tion of this solid residue is not composed of salts having a medicinal action, 
and provided also that it does not hold sulphurous gases or sulphides in 
solution. The mineral water of Plombieres contains only 0.24 gram of 
solid matter to the litre; but of this, 0.0927 gram is sodium sulphate; 
the waters of Bagneres contain only 0.227 gram solid matters, of which 
0.064 gram is composed of sulphides; it also has hydrogen sulphide in 
solution. 

As a rule, the water of " fresh " springs is cool even in summer, contains 
a much less proportion of solid matter than that mentioned above, and 
has a crisp and agreeable flavor, owing to the almost entire absence of 
organic matter and the presence of a comparatively large amount of 
dissolved oxygen. Spring-waters from limestone and dolomite formations 
contain excessive quantities of the salts of magnesium and calcium, in 
consequence of which, without being valuable as "mineral waters," their 
usefulness as drinking-water is greatly diminished or destroyed (see p. 49). 

Artesian wells may be regarded as artificial springs, formed by boring 
perpendicularly into the earth, in a low-lying district surrounded by more 
elevated ground, until a permeable layer included between two strata of 
impermeable rock is reached, the strata being so curved that their outcrop 
is in the surrounding elevated district. When such a well has been suc- 
cessfully bored, usually at great cost, it furnishes, without pumping, an 
abundant supply of water, more or less pure, according to the nature of 
the strata through which the water has percolated. The following table 
indicates the nature of the impurities present in the waters from springs 
and artesian wells: 



Origin. 



Spring near Besancon, 
France 

Spring in Surrey, England. 

Spring near Auburn, Me. . . 
Artesian well at G-renelle, 

France 

Artesian well at Trafalgar 

Square, London 

Artesian well at Dedham, 

Mass 

Artesian well at Boston .... 
Brewery Spring, Boston.. . . 



Fixed 
residue. 


Ca. 


Mg. 


CI. 


Organic 
matter. 


0.3085 
0.225 

0.0349 

0.143 

0.9915 

0.0888 

0.945 

0.2629 


0.1046 
0.0626 


0.0008 
0.0025 


0.0016 
0.0121 


0.0136 

0.0022 

0.002 

0.013 

0.019 

0.0317 

0.0288 


0.0272 
0.018S 


0.004 
0.0091 


0.0052 

0.1742 





















Authority. 



H. Deville. 
Graham, Miller 

& Hofmann. 
S. D. Hayes. 

Payen. 

Abel & Rowney. 

S. D. Hayes. 



Some of these artesian wells are of great celebrity: that at Grenelle, 
in the outskirts of Paris, has a depth of 1,748 feet, and furnishes 516 gal- 
lons per minute, the water rising to a height of 32 feet from the level of 
the ground. 

Fourth. — River-water is composed of spring-water, rain-water, and 
the drainage-water from the country through which the river flows; it con- 
tains also ice- and snow-water at all seasons, if the origin of the river be 
from a glacier or from above the snow-line; and in the lowlands in winter 
and early spring; or sea-water, if it be sufficiently near the ocean to be 
under tidal influence. River-water may, therefor, be excellent or en- 
tirely unfit for drinking. A river flowing rapidly through a granitic region 



46 



GENERAL MEDICAL CHEMISTRY. 



distant from the sea, furnishes, unless polluted by man, a pure, bright, and 
highly aerated water; while another, flowing sluggishly through rich, allu- 
vial lands, yields a muddy, unaerated water, holding large quantities of 
mineral and organic matter in solution and in suspension. 

The amount of mineral matter held in solution in river-water increases 
with the distance it has travelled. The water of a mountain torrent in 
the valley of the Isere, near its origin in a glacier, was found by Grange 
to contain 0.0201 gram of mineral matter per litre ; the water from the 
same stream, 2,000 metres (1^ mile) below, contained 0.0753 gram per 
litre. The waters of the Rhine at Bale contain 0.1694 gram of fixed resi- 
due per litre (Pagenstecher); at Strasbourg, about 80 miles below, 0.2317 
gram (H. Deville), and at Emmerich, about 400 miles below, 0.289 
gram (Midler). The purity of river -water depends largely upon the 
density of the population, and upon the nature of the industries followed 
upon its banks ; indeed, the two principal sources of the pollution of river- 
waters are the discharge into them of the sewage of cities and the waste 
products of factories. In its passage through a large city, river- water re- 
ceives organic matter, ammonia, chlorides, sulphates, phosphates, and 
carbon dioxide, while it loses oxygen. The amount of free nitrogen re- 
mains nearly the same. In the following table, compiled from the analyses 
of R. A. Smith, Graham, Miller and Hofmann, and Ashley, are indicated 
the changes which take place in the amounts of extraneous substances 
dissolved in the water of the Thames, produced during its passage 
through London — these changes occurring notwithstanding the fact that 
the sewage is discharged outside of the city, at a point below Woolwich, 
distant about twelve miles from London Bridge, and that the contamina- 
tion is caused by the addition of a quantity of filth exceedingly small as 
compared with the total sewage of the city. 



Water taken at 


O. 


1ST. 


CO a 


Solids. 


Ci. 


Organic 
matter. 


Hammersmith. . . . 
Chelsea 


4.1 
1.5 

6.25 


15.1 
16.2 
14.5 


6.46 

27\2" 
.... 


o!304 
0.4084 


0.0175 
0.0636 


.034 


Waterloo Bridge. . 
London Bridge . . . 


0.100 



The amounts of dissolved gases are given in c.c, and those of the 
solids and chlorine in grams per litre. 

The question of the most advantageous disposal of the sewage of towns 
and cities is one which, although it has been the subject of a vast amount 
of discussion and investigation, is still subjudice. If, as is unfortunately 
often the case, the sewage is discharged into the nearest stream, the water 
is contaminated to such an extent that it is not only useless for drinking, 
but also a stench in the nostrils of the inhabitants below. There is also 
an economic objection to this plan, in that a large quantity of valuable fer- 
tilizer is thus wasted. Methods have repeatedly been suggested and sub- 
jected to the test of experiment, for utilizing human excreta as fertilizers. 
These are of four kinds, and, unfortunately, are all open to objections more 
or less serious. 

In Holland and Belgium a very primitive method is followed: the de- 



NATURAL WATERS. 47 

jections are collected in cisterns or barrels, whence they are removed to 
larger depots, at which the farmers purchase their supplies as needed — us- 
ing the material without any preparation beyond fermentation and dilu- 
tion with water. In Paris the excreta are not allowed to enter the sewers, 
but are collected in cisterns, whence they are pumped at night and carried 
to a suburb, which will be easily recognized by the traveller, be he never so 
severely afflicted with catarrh. Here the liquid portions are separated 
and sold for manure under the name of " eaux vannes," and the solid por- 
tions are subjected to a slow drying process, to yield a brown, odorless fer- 
tilizer called " poudrette." These two methods of dealing with human 
excreta from cities are open to the serious objection that the material is 
allowed to collect and exhale its noxious and disgusting effluvia in the 
midst of the population, an objection most serious among the poorer house- 
holders, who, to avoid the expense of frequent cleansing of the cisterns, 
fail to use the necessary quantity of water for flushing the closets. 

Of late years frequent attempts have been made to use the mixture of 
surface-water and excreta collected from the sewers by discharging it di- 
rectly upon the land. Experiments upon a large scale have been made in 
the neighborhood of Milan, of Edinburgh, of Banbury, at Norwood, and 
at the Lodge Farm, near London. This plan, which was not attended with 
the financial success expected by its promoters, is also open to serious ob- 
jections from a sanitary point of view. It is certainly as favorable to the 
propagation of disease, especially cholera, typhoid, and entozoic diseases, 
as is the method of discharging the sewage into the rivers. 

A plan which is destined to yield the best results, when all idea of at- 
tempting to follow it with pecuniary profit as the principal object shall 
have been abandoned, is that of collecting the sewage at some point in 
the neighborhood of the city, and there subjecting it to disinfection with 
a view to rendering its subsequent use as a fertilizer safe and inoffensive. 

It is an undeniable fact that organic matter in solution or in suspen- 
sion in rapidly moving water is decomposed and oxidized more or less 
quickly; urea is soon decomposed into carbonic anhydride and ammonia; al- 
buminoid substances are much more slowly oxidized, their nitrogen being 
converted into nitrates, nitrites, and ammoniacal compounds. Although 
this decomposition takes place in the course of a few miles in a stream 
whose current is rapid, provided the admixture of sewage-matter be not 
in too great proportion, it is impossible to state at what a distance from 
the source of contamination the water of a river receiving sewage dur- 
ing an epidemic of typhoid or of cholera, would become incapable of com- 
municating the disease, if, indeed, there be any limit. 

Quite as serious a source of contamination of river-water exists in the 
discharge into it of the waste products from factories, etc. These con- 
taminations are as various in their nature as the processes which give rise 
to them; the question of their disposal is, although much more simple 
than that in which sewage is concerned, not likely to be quickly solved, 
owing to the magnitude of the financial interests involved. Manufac- 
turers should be obliged to discharge their waste products, when these 
are of such a nature as neither to contaminate the air, nor yet to impede 
navigation, only into rivers whose waters are naturally unfit for drink- 
ing. When from any cause this course cannot be followed, they should 
adopt some process (which will certainly be devised pro re nata) of dis- 
posing of their refuse in such a way as to avoid pollution of the water. 

The nature and amount of the substances held in solution in river- 



48 GENERAL MEDICAL CHEMISTRY. 

water varies materially with the season. The warmer the water the more 
solid and the less gaseous matter it contains. In warm weather the ten- 
dency of organic matter to putrefaction is greater, as is also the rapidity 
of its destruction by oxidation. During those periods when water- 
courses are swollen by rains and by the melting of snow, the amount of 
dissolved solid matter is relatively diminished, while the amount of sus- 
pended solids is increased. River-water, at the first part of the flood 
period, contains an amount of chlorine much greater in proportion to 
total solids and to hardness thari at other periods. The water which 
comes down during the first part of the flood has not penetratdd deeply 
into the earth, and has therefor had but little opportunity of becoming- 
charged with earthy salts; it has, however, dissolved the more soluble 
chlorides from the surface. At later periods the water, penetrating more 
deeply below the surface, becomes more highly charged with calcareous 
salts. 

Fifth — Lake-water. — Fresh lakes, being, as a rule, simply expansions 
of rivers, or points where many of their tributaries unite, their water is 
very similar to that of the rivers flowing into or out of them, with the 
exception that, as the lakes expose a large surface to the air, and as the 
water is kept in motion both by the current and by the action of the 
winds, the removal of organic matter by oxidation is more active than in 
rivers not having a very rapid current. Lakes form natural reservoirs 
from which the water-supply of many cities is obtained. Those cities 
situated upon the borders of large lakes are assured of an abundant sup- 
ply of pure water, it being only required to raise it to a sufficient height 
for distribution. Municipalities less fortunately situated resort to the 
construction of more or less elaborate works, for the collection and stor- 
age of water from a system of lakes and rivers. 

Sixth — Well-water may be very good or very bad. In some in- 
stances the well is simply a collecting reservoir dug over a natural spring. 
When this is the case, if it be in such a situation as to be free from 
contamination, the water is essentially spring-water (q. v.). In most 
cases, however, a well is simply a hole, deep or shallow, with walls well 
or badly constructed, into which the surface-water percolates from the 
thin stratum through which the well is dug. Such water is almost always 
highly charged with organic matter, insipid or sweetish in taste, and 
should be carefully avoided. 

But the character of well-water, whatever its source, depends largely 
upon its position. As a rule, wells are constructed near to human habita- 
tions, and are thus very liable to contamination with organic matter, either 
from the surface, or, more frequently, by the breaking of a house-drain 
and the filtration of its contents, through a few feet of intervening soil, 
into the water of the well (see p. 52). 

Of late years "driven wells" have been largely resorted to in this 
country. They are formed by driving a pointed iron tube into the earth, 
increasing the length of tube by sections and removing any earth which 
(imay have found its way within the tube, until a supply of water is ob- 
tained, either by its spontaneous rise in the tube, or, more commonly, by 
pumping. The water so obtained is similar in character to that from 
surface-wells, and, while it may be good where the location is in an open 
and unmanured location, it is to be looked upon with grave suspicion if 
the well be driven in any situation where the surface-water is liable 
to become contaminated with the excreta of men or animals. 



IMPURITIES IN POTABLE WATEK. 49 

Impurities in Potable Water. 



Characters of a good ivater. — It should be cool, limpid, and odorless. 
It should have an agreeable taste, neither flat, salty, nor sweetish, and it 
should dissolve soap readily, without the formation of insoluble, flocculent 
material. Any water which does not possess these qualities is not fit for 
drinking ; but it is by no means true that any water which does possess 
them is not to be looked upon with suspicion. To determine whether or 
no any given water is potable, a more careful examination into the nature 
and quantity of foreign substances present is necessary. These sub- 
stances may be either in solution or in suspension. 

First — Total solids. — We have seen that all natural waters are more 
or less charged with solid mineral matter, a certain proportion of which 
seems to be necessary to health. On the other hand, if the amount of 
solid matter dissolved be excessive, the water is both unpalatable and 
unhealthy. In the following table is given the number of grams per litre 
of total solids in various waters : 



Distilled water . 0017 

London — Thames Co . 2646 

London — New River Co . . 0.2509 

London— Kent Co 0.3780 

Rhine, at Basle 0.1694 

Seine, at Bercy 0.2544 

Spree, at Berlin . 114 

Glasgow — Loch Katrine . . 0.0328 



Croton 0.0918 

Boston — Cochituate 0.0548 

Charlestown— Mystic . 0972 

Copenhagen 1 . 700 

Atlantic — surface 34.700 

Dead Sea— surface 27.078 

Dead Sea— 300 metres. . .278.135 



The amount of total solids in potable waters varies from 0.05 to 0.4 
gram per litre, the amount being*, as a rule, less in the waters supplied 
to American cities than in those consumed by the urban populations of 
Europe. The solids dissolved in water, their nature not being taken into 
consideration, do not impair its usefulness as a drink, unless they be 
present in a quantity greater than 0.4 to 0.5 gram per litre. 

The determination of the amount of total solids is easily conducted : 
25 c.c. of the filtered * water are evaporated to dryness in a previously 
weighed platinum dish over a water-bath. After cooling in a drying-box, 
the dish, with the contained residue, is weighed ; the increase in weight, 
multiplied by 40, gives the amount of total solids per litre. 

Second — Hardness. — Of the solid matters dissolved in potable waters, 
the greater part is usually made up of salts of calcium, accompanied, as a 
rule, by small quantities of salts of magnesium. The calcium salt present 
is usually the carbonate or the sulphate; sometimes the chloride, phos- 
phate, or nitrate. Calcium carbonate is almost insoluble in pure water; 
but in water charged with carbon dioxide a more soluble bicarbonate 
is formed, which remains in solution until the carbon dioxide is ex- 
pelled by heat, whenever the carbonate is present in quantity greater 
than 0.5 gram per litre. The sulphate is present, being sparingly soluble, 
in many excellent waters. In quantity it should not exceed 0.02 gram 
per litre. The presence of the phosphate is probably more general than 
published analyses would lead one to suppose, as it is widely disseminated 

* Suspended solids must be determined by the method given on p. 57. 
4 



50 GENERAL MEDICAL CHEMISTRY. 

in the mineral world, and the processes used for determining- phosphoric 
acid lack accuracy when applied to such small quantities as we have here 
to deal with. The chloride is rarely present, and only in small quantity. 
The nitrate is only found in waters contaminated with organic matter, at 
the expense of whose nitrogen the nitric acid is formed by oxidation. 

A water which contains an excess of calcium salts is said to be hard, 
while one not so charged is said to be soft. If the hardness be due to the 
presence of the carbonate, it is temporary, as, upon the application of 
heat, carbon dioxide is driven off, and the excess of carbonate, being no 
longer soluble, is precipitated. A permanently hard water owes its hard- 
ness to the presence of the sulphate, which remains in solution after heat- 
ing, being dissolved simply by virtue of its own solubility. 

It is a matter of common experience that a hard water is not as ser- 
viceable for domestic purposes as soft water. If we attempt to dissolve 
soap in a water charged with calcic and magnesic salts, the first portions 
are decomposed with the formation of the insoluble calcium and magne- 
sium palmitate and oleate, which separate as nocculent precipitates, and 
not until the earthy salts have thus been removed will the water be capa- 
ble of dissolving or forming a lather with soap. Vegetables, when boiled 
in hard water, do not soften as readily as when the water is soft; moreover, 
a hard water is difficult of digestion, and is liable to produce disorders of 
digestion, especially in those unaccustomed to its use. 

Magnesium salts, sulphate and carbonate, frequently accompany the cor- 
responding calcium compounds, although in much smaller quantity. Their 
influence upon the quality of the water is the same as that of the calcium 
salts, with the difference that if the quantity of magnesic salt exceeds 0.02 
gram per litre, the water is to some extent purgative. The opinion advanced 
by Grange and sustained by others, that the occurrence of goitre and 
cretinism is due to an excess of magnesium salts in the water, is not well 
founded. Analysis has shown the presence of greater quantities of mag- 
nesium salts in the water of districts where these diseases are unknown 
than exists in the waters used in localities where they are very prevalent. 

Although an excess of calcareous salts in water renders it unfit for do- 
mestic use, within proper limits, 0.3 gram per litre, the carbonate and 
phosphate of calcium are not only not deleterious, but beneficial constit- 
uents, as they supply a proportion of those salts required by the economy, 
especially in the first years of life. 

It is rarely necessary to determine the amount of calcium and magne- 
sium salts present in water with accuracy. It is, however, frequently of 
importance to determine the degree of hardness, which may be measured 
with tolerable exactness by means of a process suggested by Dr. Clark in 
1847, and based upon the soap-destroying power of the earthy salts. The 
method, as given by Wanklyn and as usually applied, is very simple. 
Seventy cubic centimetres of the water to be tested are placed in a glass- 
stoppered bottle having a capacity of 250 c.c. From a burette an alco- 
holic solution of soap is added, and after each addition the bottle is shaken 
and laid upon its side for five minutes. If at the end of that time the 
lather remains, enough soap-solution has been added; if not, the addition 
must be continued until the lather persists for five minutes. If more than 
16 c.c. of soap-solution are used, 70 c.c. of distilled water must be added, 
as a lather is not readily formed if the proportion of alcohol become too 
great. Having added sufficient soap-solution, the degree of hardness is 
indicated by the number of cubic centimetres of soap-solution used minus 1. 
Thus, if 15 c.c. soap-solution have been used, the degree of hardness is 14. 



IMPURITIES IN POTABLE WATER. 51 

If from the degree of hardness we subtract 1, we have approximately the 
number of grains of calcium carbonate, or of salts having an equal soap- 
destroying power, in a gallon of the water. 

To prepare the soap-solution, air-dried white castile soap is reduced to 
thin shavings, of which 10 grams are dissolved in a litre of weak alcohol, 
having a specific gravity of about 0.949. The solution must not be fil- 
tered; usually it is clear, but, if turbid, it should be shaken before using. 

Having made the soap-solution, it is necessary to determine its actual 
strength, as soap is a substance which cannot be accurately weighed. To 
this end a solution of calcium chloride of known strength is made by dis- 
solving 1.11 gram of pure, recently fused calcic chloride in a litre of water; 
10 c.c. of this solution, mixed with 60 c.c. of distilled water, should require, 
for the formation of a persistent lather, 11 c.c. of soap-solution. If more 
or less of the soap-solution be required, it must be concentrated or diluted 
in the proportion of the deficiency or excess to bring it to the proper 
strength. 

By this method the total hardness is determined. If it be desirable 
to know what portion of this is temporary or permanent, the total hard- 
ness is first determined. Another sample of the water is then boiled, and 
from this 70 c.c. are taken after filtration, in which the permanent hard- 
ness is determined as above ; the difference is temporary hardness. 

It sometimes occurs that a water, comparatively pure as to organic 
matters, exhibits a tendency to produce diarrhoea ; in this case it is well 
to determine the amount of magnesian salts present. A litre of water is 
evaporated to dryness in a platinum dish; the residue is moistened with 
hydrochloric acid, a small quantity of water is added, and the solution fil- 
tered. To the united filtrate and washings ammonium hydrate and solu- 
tion of ammonium oxalate are added in excess; the liquid is then heated 
and filtered. To the filtrate more ammonia is added, and the mixture al- 
lowed to stand. If after twelve hours a precipitate have formed, the fluid 
is again filtered. To the clear liquid, which should not be more than 40 c.c. 
in bulk, solution of phosphate of sodium and ammonium hydrate are 
added in excess, and the mixture set aside for twenty-four hours. The 
precipitate is now collected on a filter, washed with ammoniacal water, 
dried, ignited, and weighed. The weight of the residue, multiplied by 
O.36036, equals the weight of magnesia in a litre of the water. 

A good drinking-water should not have a hardness of more than 15, 
and should not contain more than 0.015 gram per litre of magnesium. 

Third — Chlorides. — The chlorides of the alkaline and earthy metals oc- 
cur in varying quantity in all natural water. The occurrence of these salts 
in quantities not sufficient to render their presence readily detectable by 
the taste is of no importance per se y but, in connection with the presence 
of organic matter, a determination of the amount of chlorine affords a 
valuable index to the probable source of the organic matter. The most 
dangerous of organic contaminations is that by admixture of animal ex- 
creta ; the presence of vegetable organic matter is, comparatively speak- 
ing, innocuous. Vegetable contamination brings with it a very small 
amount of chlorine, while urine, which, when the water is polluted with 
sewage, forms the bulk of the contaminating admixture, contains large 
quantities of chlorides. If, therefor, a well-water be found to contain an 
excess of chlorides, it is to be looked upon with suspicion; and if at the 
same time there be an excess of nitrogenized material, there remains but 
small doubt that the well contains diluted urine. So true is this that at 
times, when results must be obtained rapidly, as during an epidemic, the 



52 GENERAL MEDICAL CHEMISTRY. 

best course for the analyst to pursue is to determine the amount of 
chlorine in each source of supply, and to condemn those containing more 
than .015 gram per litre (one grain per gallon) of chlorine. Whenever 
it is possible, however, a determination of organic matter should be made,, 
and the result considered in connection with the quantity of chlorine 
before deciding for or against a water. 

The determination of the amount of chlorine is easily effected by 
means of a solution of silver nitrate containing 4.79 grams per litre: 
100 c.c. of the water to be tested are placed in a beaker ; a few drops of 
a solution of potassium chromate, enough to communicate a distinctly 
yellow tinge, are added ; the reaction is determined, and, if necessary, 
the mixture is rendered faintly alkaline by the addition of a solution of 
sodium carbonate. The silver solution is now allowed to flow in, drop 
by drop, from a burette, the fluid in the beaker being constantly stirred, 
until the white precipitate assumes & faint reddish tinge. At this time 
the reading of the burette is taken; each cubic centimetre of silver solu- 
tion added represents 0.001 gram chlorine in 100 c.c. of water, or 0.01 
per litre. 

Fourth — Organic matter. — Although the presence in a water of or- 
ganic substances, i. e., substances into whose composition carbon enters 
as an element, cannot be considered as condemnatory, there is no reason 
for doubting that the most serious of contaminations of potable waters 
are those caused by the presence of organic matters containing nitrogen, 
both from the putrescible nature of these substances, and from the in- 
dication afforded by their presence of the existence in the water of 
animal excreta, as well as the presence under suitable conditions of the 
causes of the disease, be they germs or poisons. Every potable water 
contains small quantities of organic matter of vegetable origin, which are 
of no significance, provided the quantity be small and the water be taken 
from a river, lake, or other body of moving water. If, however, a well- 
water, or other still water, contain much vegetable organic matter (its 
vegetable nature being indicated by the absence or deficiency of chlorides), 
the source is to be condemned for that reason alone. 

A much more serious organic contamination is with nitrogenous- 
matter of animal origin. Although our knowledge of the nature of the 
products of decomposition of these substances is still quite crude, it is 
certain that among them are substances having a pronounced tendency 
to produce low forms of fever, and to render those subjected to their in- 
fluence ready victims to epidemic disorders. Whatever ill effects may 
result from the use of waters polluted by the excreta of healthy individ- 
uals, the evil becomes much more serious during the prevalence of certain 
diseases. There can remain no doubt that cholera and typhoid are trans- 
mitted largely, if not exclusively, by the use of water into which the 
excreta of a sufferer from the disease have found their way. 

The investigations of Mr. J. N. Radcliffe, on the cholera in London 
in 1866, have shown that the disease was sharply limited to those por- 
tions of the metropolis supplied with water from the Old Ford reservoirs 
of the East London Water Company, the earliest unquestionable out- 
breaks of the disease having appeared within half a mile of these reser- 
voirs.* In a subsequent report Dr. Buchanan traced the source of the 
epidemic of typhoid, which occurred at Guildford, directly to contamina- 
tion of water-supply. The town is supplied with a double system of high 

* Report of the Medical Officer of the Privy Council, 1866 (9th). p. 295-331. 



IMPUlilTIES IX POTABLE WATER. 53 

and low distribution, and with very few exceptions the disease was 
limited to those using the high service.* In the same year epidemics of 
typhoid occurred also at Winterton and at Terling; in both instances 
they were distinctly referable to contamination of the water with sewage. | 
Similar conclusions have been arrived at in investigations of the causes of 
many other epidemics. 

Several processes have been devised for the determination of the 
amount of organic matter present in drinking-water; of these some are 
very readily applied, and are inaccurate in proportion to their facility. 
Probably the method best adapted to use by the practitioner in an im- 
ergency is that which has the least claim to exactness of results. This 
consists in simply partially filling a clean bottle with the water to be 
tested, and, after strong agitation, inhaling the air of the bottle through 
the nostrils. The presence or absence of an injurious amount of organic 
matter is inferred from the presence or absence of a disagreeable odor, 
however faint, of the inhaled air. The only advantage of this method is 
the facility of its application; it is exceedingly rough, and should be used 
■only when time presses. 

Another method is the permanganate test, which must be mentioned 
here that it may be avoided, especially as it has received a quasi- 
official indorsement at the hands of the New York Board of Health. In 
the report of that body for 1873, J directions are given for testing water 
by dropping into it a solution of potassium permanganate and by the 
discharge of color determining not only the presence, but also the 
amount of organic matter in the water. Drs. Frankland, Wanklyn, and 
Fox have clearly shown that the process is vitiated by both plus and 
minus errors. Any substance capable of abstracting oxygen from the 
permanganate will effect its decolorization, whether the substance be or- 
ganic or not. On the other hand, in the conditions under which the test 
is applied, organic substances of an albuminoid nature and urea are not 
readily oxidized by permanganate. By the use of this test, therefor, a 
water may be condemned which contains a very small amount of organic 
matter while a water highly charged with impurities of the worst type 
would be passed without suspicion. 

There are at present but two methods for the determination of organic 
matter in potable water which are worthy of serious consideration. 
These are Frankland and Armstrong's process, and Wanklyn's process. 
Frankland and Armstrong's method § is one which can only be applied in 
a fully appointed laboratory, and which, even under the most favorable 
conditions, is open to the serious objection that, owing to the small quan- 
tities to be determined and to the nature of the process, the experimental 
error may represent a quantity greater than that of the substance to be 
determined. 

The process which is now almost exclusively used by chemists is 
that first suggested by Wanklyn, Chapman, and Smith, in 1867, || and is 
based upon the following reactions: 1st, the Nessler test for ammonia; 
i. e., the production of a yellow color by ammonia in a saturated alka- 
line solution of mercuric iodide in potassium iodide; and 2d, the decom- 
position of organic nitrogenous substances, with production of ammonia, 

* Report of Medical Officer of the Privy Council, 18G7 (10th), p. 34. 
f Dr. R. T. Thome, ib., pp. 28, 41. t P- 574. 

§ Journ. Ch. Soc. N. S., vi., 77. 

j Ibid., v., 448; id. vi., 152, 161. Wanklyn: Water Analysis, 3d ed. 3, 2. Fox: 
Water Analysis, 15. 



54 GENERAL MEDICAL CHEMISTRY. 

when they are boiled with a highly alkaline solution of potassium per- 
manganate. 

For the application of this testj the following solutions are required: 

a. Alkaline solution of potassium permanganate, made by dissolv- 
ing 200 grams of potassium hydrate and 8 grams of potassium permanga- 
nate in a litre of water; the solution is boiled down to about 725 c.c., 
cooled, and brought to its original bulk by the addition of the requisite 
quantity of boiled distilled water. 

b. Nessler reagent. — To prepare this, 35 grams of potassium iodide 
and 13 grams of mercuric chloride are dissolved in 800 c.c. of water, by 
the aid of heat and agitation. A cold saturated solution of mercuric 
chloride is then added, drop by drop, until the red precipitate which is 
formed is no longer redissolved on agitating the liquid; 160 grams of po- 
tassium hydrate are then dissolved in the liquid, to which, finally, a slight 
excess of mercuric chloride solution is added, and the bulk made up to 
one litre by the addition of water. The solution is then set aside until 
the red precipitate has subsided, when the clear, faintly yellowish liquid 
is decanted and preserved in well-stoppered bottles, which should not be 
too large and should be completely filled. 

The glass stoppers of the bottles containing a and b should be well 
coated with paraffine, to prevent adhesion. 

c. Standard solutions of ammonia. — These are a stronger and a weaker. 
The first is made by dissolving 3.15 grams of ammonium chloride in a 
litre of water; the second, by mixing 1 volume of the first with 90 
volumes of distilled water. The weaker solution, which contains 0.00001 
gram (yjj-y- milligram) of ammonia (NH 3 ) in each cubic centimetre, is the 
one which is used in examinations of water, the more concentrated solu- 
tion serving simply for the convenient preparation of the other. 

d. A saturated solution of sodium carbonate. 

e. Distilled water. — The middle third of the distillate; 100 c.c. of 
which in a cylinder should not be perceptibly colored in ten minutes by 
the addition of 2 c.c. of Nessler reagent. 

The testing of a water is conducted as follows: half a litre oi the 
water to be tested (it is scarcely necessary to state that, before taking 
the sample, the demijohn or other vessel containing the water must be 
thoroughly shaken) is introduced, by a funnel, into a tubulated retort 
capable of holding one litre. If the water be acid, which is rarely the 
case, 10 c.c. of the solution of sodium carbonate d are added. Having 
connected the retort with a Liebig's condenser, the joint being made 
tight by a packing of moistened filter-paper, the water is made to boil as 
soon as possible by applying the flame of a Bunsen burner, brought close 
to the bottom of the naked retort (there is but little danger of fracture 
if the flame do not reach above the level of liquid inside). The first 
50 c.c. of distillate are collected in a cylindrical vessel of clear glass, 
about an inch in diameter. The following 150 c.c. are collected and 
thrown away, after which the fire is withdrawn. While these are pass- 
ing over, the first 50 c.c. are Nesslerized [vide infra), and the result, plus 
one-third as much again, is the amount of free ammonia contained in the 
half -litre of water. 

When 200 c.c. have distilled over, all the free ammonia has been 
removed, and it now remains to decompose the organic material, and 
determine the amount of ammonia formed. To effect this, 50 c.c. of the 
permanganate solution a are added through the funnel to the contents 
of the retort, which is shaken, stoppered, and again heated. The dis- 



IMPURITIES IN POTABLE WATEB. 55 

tillate is now collected in separate portions of 50 c.c. each, in glass cylin- 
ders, until three such portions have been collected. These are then 
separately Nesslerized as follows: 2 c.c. of the Nessler reagent are added 
to the sample of 50 c.c. of distillate; if ammonia be present, a yellow or 
brown color will be produced, dark in proportion to the quantity of 
ammonia present. Into another cylinder a given quantity of the stand- 
ard solution of ammonia c is allowed to flow from a burette; enough 
water is added to make the bulk up to 50 c.c, and then 2 c.c. of Nessler 
reagent. This cylinder, and that containing the 50 c.c. of Nesslerized 
distillate, are then placed side by side upon a sheet of white paper and 
their color examined. If the shade of color in the two cylinders be 
exactly the same, the 50 c.c. of distillate contain the same amount of 
ammonia as the quantity of standard solution of ammonia used. If the 
colors be different in intensity, another comparison-cylinder must be 
arranged, using more or less of the standard solution, as the first com- 
parison-cylinder was lighter or darker than the distillate. When the 
proper similarity of shades has been attained, the number of cubic centi- 
metres of the standard solution used is determined by the reading on the 
burette. This process, which, with a little practice, is neither difficult nor 
tedious, is to be repeated with the first 50 c.c. of distillate and with the 
three portions of 50 c.c. each, distilled after the addition of the perman- 
ganate solution. If, for example, it required 1 c.c. of standard solution 
in Nesslerizing the first 50 c.c, and for the others 3.5 c.c, 1.5 c.c, and 
0.2 c.c, the following is the result and the usual method of recording it: 

Free ammonia 01 milligr. 

Correction 003 milligr. 

.013 milligr. 

Free ammonia per litre 026 milligr. 

Albuminoid ammonia . 035 milligr. 

Albuminoid ammonia 015 milligr. 

Albuminoid ammonia 002 milligr. 

.052 milligr. 

Albuminoid ammonia, per litre .104 milligr. 

Concerning the deductions to be drawn from the determination of 
ammonia, Mr. Wanklyn* says: " If a water yield 0.00 parts of albuminoid 
ammonia per million, it may be passed as organically pure, despite of 
much free ammonia and chlorides; and if, indeed, the albuminoid ammo- 
nia amount to .02, or to less than 0.05 part per million, f the water 
belongs to the class of very pure water. When the albuminoid ammo- 
nia amounts to .05, then the proportion of free ammonia becomes an 
element in the calculation; and I should be inclined to regard with some 
suspicion a water yielding a considerable quantity of free ammonia along 
with .05 part of albuminoid ammonia per million. Free ammonia, how- 
ever, being absent or very small, a water should not be condemned unless 
the albuminoid ammonia reaches something like 0.10 per million. Albu- 

* Water Analysis, 3d ed., 51. f Milligrams per litre. 



56 GENERAL MEDICAL CHEMISTRY. 

minoid ammonia above 0.10 per million begins to be a very suspicious 
sign, and over 0.15 ought to condemn a water absolutely. The absence 
of chlorine, or the absence of more than one grain of chlorine per gallon, 
is a sign that the organic impurity is of vegetable rather than animal 
origin; but it would be a great mistake to allow water highly contami- 
nated with vegetable matter to be taken for domestic use." 

Fifth — Nitrates. — The existence and quantity of alkaline nitrates in 
water were formerly regarded as of much greater importance than that 
now accorded. They were considered as indicating, if not the actual sew- 
age present, at least the amount of previous contamination, for the rea- 
son that they are the principal ultimate products of the oxidation of 
nitrogen contained in organic substances. They exist, however, also in 
waters perfectly free from organic contamination as well as in rain-water, 
being taken up by the former in its passage through certain geological 
strata, and being formed in the latter probably by direct union of the 
nitrogen and oxygen of the air. 

• Sixth — Poisonous metals. — The metals most liable to occur in potable 
waters are iron, copper, and lead. 

a. Iron may be dissolved by water either during its passage through 
ferruginous strata in the earth, or by conduction through iron pipes. Cer- 
tain ferruginous waters are valuable medicinal agents, and may contain 
as much as 607 milligrams of salts of iron to the litre. For ordinary uses, 
however, a water should not contain more than three milligrams per litre 
of iron. The amount of iron dissolved by water in passing through iron 
pipes is exceedingly small. The distribution of water in large cities, and 
frequently the main supply also, is through such channels. 

Mr. A. W. Blyth has also shown that water containing organic mat- 
ter is purified, to a large extent, of these contaminations by passage 
through iron pipes. 

(3. Copper. — Drinking-water is not liable to become contaminated 
with the salts of this element except when it comes in contact with deposits 
of the metal, or of its ores in its passage through the earth. The experi- 
ments of Muir have shown that pure water would not dissolve coppe'r, but 
that water containing carbon dioxide, especially when also containing cal- 
cium chloride and ammonium nitrate, would dissolve it in considerable 
quantity. 

y. Lead. — The most serious, as well as the most common metallic 
contamination of water, is that with lead. Although a water contain a 
very small quantity of lead salts, there is no doubt that its continued use 
will produce well-marked cases of chronic lead-poisoning, and numerous 
instances are recorded in which the disorder has been traced directly to 
this cause, and has ceased with its removal. 

The power possessed by a water of dissolving lead varies materially 
with the nature of the substances which it holds in solution. The pres- 
ence of nitrates is favorable to the solution of lead, an influence which is, 
however, much diminished by the simultaneous presence of other salts. A 
water highly charged with oxygen dissolves lead readily, especially if the 
metallic surface be so exposed to the action of the water as to be alter- 
nately acted upon by it and by the air. On the other hand, waters 
containing carbonates or free carbonic acid may be left in contact with 
lead with comparative impunity, owing to the formation of a protective 
coating of the insoluble carbonate of lead on the surface of the metal. 
This does not apply, however, to water charged with a large excess of 
carbon dioxide under pressure. It will be observed from what precedes 



IMPURITIES IN POTABLE WATER. y? 

that of all natural waters that most liable to contamination with lead is 
rain-water; it contains ammonium nitrate with very small quantities of 
other salts; and it is highly aerated, but contains no carbonates and com- 
paratively small quantities of carbon dioxide. Obviously, therefor, rain- 
water should neither be collected from a leaden roof, nor stored in leaden 
tanks, nor drank after having been long in contact with lead pipes. As a 
rule, the purer the water the more liable it is to dissolve lead when brought 
in contact with that metal, especially if the contact occur when the water 
is at a high temperature, or when it lasts for a long period. 

It has been proposed, in order to avoid the solution of lead, to use 
pipes of lead coated internally with block tin. Unfortunately, however, 
it has been found that wherever a fault occurred in the coating, the lead 
is dissolved much more rapidly than from pipes made entirely of lead. 
Moreover, tin is a substance which is by no means insoluble in water, 
its solubility being materially increased when it is alloyed with even a 
very small proportion of lead. 

To determine the power of water for dissolving lead, take two tum- 
blers of the water to be tested ; in one place a piece of lead, whose 
surface has been scraped bright, and allow them to stand twenty-four 
hours. At the end of that time remove the lead and pass sulphuretted hy- 
drogen through the water in both tumblers : if the one which contained 
the metal become perceptibly darker than the other, the water has a 
power of dissolving lead such as to render its contact with surfaces of 
that metal dangerous if prolonged beyond a short time. 

The testing of water for poisonous metals is a very simple matter, and 
consists in adding to the water, in a porcelain capsule, some solution of 
ammonium sulphydrate. If the water become perceptibly darker after 
the addition of the reagent, it contains a poisonous metal, whose nature 
is then to be determined. Having determined whether the metal is iron, 
copper, or lead, a quantitative determination may be made by imitating 
the shade of color produced by ammonium sulphydrate in a given bulk of 
the water, with a standard solution of a salt of the corresponding metal 
and ammonium sulphydrate; the volume of the standard solution used 
containing the same amount of the metal as the volume of water tested. The 
standard solutions are the following : for iron, 4.96 grams of ferrous sul- 
phate dissolved in 1 litre of water ; each cubic centimetre contains 0.001 
gram iron. For copper, 3.93 grams of cupric sulphate dissolved in 1 litre 
of water ; each cubic centimetre contains 0.001 gram copper. For lead, 
1.66 gram of lead acetate in 1 litre of water; each cubic centimetre con- 
tains 0.001 gram lead. 

Seventh — Suspended solids. — Most natural waters deposit, on standing, 
more or less solid insoluble material. These substances have been either 
suspended mechanically in the water, which deposits them when it re- 
mains at rest, or they have been in solution and are deposited by becom- 
ing insoluble as the water is deprived of carbon dioxide by exposure to 
air and by relief from pressure. 

The suspended particles should be collected by subsidence in a conical 
glass, and should be examined microscopically for low forms of animal 
and vegetable life. The quantity of suspended solids is determined by 
passing a litre of the turbid water through a dried and weighed filter, 
which, with the collected deposit, is again dried and weighed. The dif- 
ference between the two weights is the weight of suspended matter in a 
litre of the water. 

Purification of water. — The artificial means of rendering a more or 



58 GENERAL MEDICAL CHEMISTRY. 

less contaminated water fit for use are of five kinds : 1. Distillation; 
2. Subsidence; 3. Filtration; 4. Precipitation; 5. Boiling-. 

The method by distillation is used in the laboratory when a very pure 
water is desired, and also at sea upon steamships, and even on sailing 1 
vessels upon occasion. Distilled water is, however, too pure for continued 
use, being hard of digestion, and flat to the taste from the absence of 
gases and of solid matter in solution. When circumstances oblige the 
use of such water, it should be agitated with air, and should be charged 
with inorganic matter to the extent of about 0.15 gram each of calcic 
bicarbonate and sodium chloride to the litre. 

Purification by subsidence is adopted only as an adjunct to precipita- 
tion and filtration, and for the separation of the heavier particles of sus- 
pended matter. 

The ideal process of filtration consists in the separation of all particles 
of suspended matter, without any alteration of such substances as are 
held in solution. In the filtration of potable waters on a large scale, 
however, the more minute particles of suspended matters are only par- 
tially separated, while, on the other hand, an important change in the dis- 
solved materials takes place, at least in certain kinds of filters, in the oxi- 
dation of organic matters, whether in solution or in suspension. In the 
filtration of large quantities of water it is passed through sand or char- 
coal, or through both substances arranged in alternate layers. Filtration 
through charcoal is much more effective than that through sand, owing- 
to the much greater activity of the oxidation of nitrogenized organic 
matter in the former case. 

Precipitation processes are only adapted to hard waters, and are de- 
signed to separate the excess of calcium salt, and at the same time a con- 
siderable quantity of organic matter, which is mechanically carried down 
with the precipitate. The method usually followed consists in the addi- 
tion of lime (in the form of lime-water), in just sufficient quantity to 
neutralize the excess of carbon dioxide present in the water. The added 
lime, together with the calcium salt naturally present in the water, is 
then precipitated, except that small portion of calcium carbonate which 
the water, freed of carbon dioxide, is capable of dissolving. To deter- 
mine when sufficient lime-water has been added, take a sample from time 
to time during the addition, and test it with solution of silver nitrate 
until a brown precipitate is formed. At this point cease the addition of 
lime-water and mix the limed water with further portions of the hard 
water, until a sample, treated with silver-nitrate solution, gives a yellowish 
in place of a brown color. The purification of water by boiling can only 
be carried on upon a small scale ; it is, however, of great value for the 
softening of temporarily hard waters, and for the destruction of organized 
impurities, for which latter purpose it should never be neglected during 
outbreaks of cholera and typhoid, if, indeed, water be drank at all at 
such times. 



Mineral Waters. 

Under this head are classed waters charged to such an extent with dis- 
solved substances, or having a temperature such as to render them avail- 
able for therapeutical uses. As a rule, spring-water has a temperature 
less than 15°, but there are man}' springs whose waters are much warmer. 
When their temperature is higher than 20° they are known as thermal 



MINERAL WATERS. 59* 

springs, and are frequently of therapeutical value independently of the 
nature of their dissolved solids, which is exceedingly various. Among 
the most noted thermal springs are those of Wildbad, 35.5° ; Warmbrunn, 
38° ; Toplitz, 49° ; Buxton, 28° ; Clifton, 30° ; Chaudes-Aigues, 81° ; 
Ems, 46° ; Carlsbad, 73° ; Arkansas Hot Springs from 40.5° to 66° ; Vir- 
ginia Hot Springs, 37.8° to 41°. The water of the great Geyser in Ice- 
land has a temperature of over 100° in the centre. 

The composition of mineral waters varies greatly, according to the 
nature of the strata or veins through which the water passes, and to the 
conditions of pressure and previous composition under which it is in con- 
tact with these deposits. Waters of very different comjDosition in some 
localities come to the surface in close proximity to each other, as at 
Saratoga Springs, where the Congress and Columbian springs, differing 
widely from each other in their chemical and therapeutical properties, 
are only a few rods apart. 

The substances almost universally present in mineral waters are: 
oxygen, nitrogen, carbon dioxide, sodium carbonate, bicarbonate, sul- 
phate and chloride, calcium carbonate and bicarbonate. Of substances 
occasionally present the most important are: sulphydric acid, sulphides 
of sodium, iron and magnesium,' bromides and iodides of sodium and 
magnesium, calcium and magnesium chlorides, carbonate, bicarbonate, 
sulphate, peroxide and crenate of iron, silicates of sodium, calcium, mag- 
nesium and iron, aluminium salts, salts of lithium, caesium and rubidium, 
free sulphuric, silicic, arsenic and boric acids, and ammoniacal salts. 

Although a sharply defined classification of mineral waters is not pos- 
sible, one which is useful, if not accurate, may be made, based upon the 
predominance of some constituent or constituents which impart to the 
water a well-defined therapeutic value. A classification which has been 
generally adopted is into five classes: 

First — Acidulous waters, those whose value depends upon the pres- 
ence of carbon dioxide. 

Second — Alkaline waters, those containing a notable proportion of 
carbonates, or bicarbonates of sodium, potassium, or lithium. 

Third — Chalybeate waters, those charged with compounds of iron. 

Fourth — Saline loaters, those containing neutral salts in considerable 
quantity. 

Fifth — Sidphurous icaters, those holding hydrogen sulphide, or a 
metallic sulphide in solution. 

Besides those waters which may be classed under one of the above 
heads, there are others which, containing some active substance not 
usually present in natural waters, such as alum, free sulphuric acid, or 
arsenical compounds, may for the present be placed in a sixth class. 

Acidulous waters. — These waters, of which the artificially prepared 
carbonic water, or soda-ioater, may be considered the type, contain but 
small quantities of solid matters in solution, the most abundant being 
the bicarbonates of sodium and of calcium, and sodium chloride. They 
are always cool, fresh, and sparkling, owing to the presence in them of 
carbon dioxide in considerable quantity, and to the absence of hydrogen 
or other sulphides. 

Alkaline waters. — The temperature of waters of this class is usually 
above 20°, although some are cooler. They are alkaline in reaction, 
some sufficiently so to have a soapy taste, others only after expulsion of 
the free carbon dioxide, which they contain in very variable proportion. 
Their principal solid constituents are the bicarbonates of sodium, calcium, 



60 GENERAL MEDICAL CHEMISTRY. 

magnesium, and sometimes lithium. Their tenure in sodium chloride is 
usually less than that of the acidulous waters. 

Chalybeate waters. — Iron, being widely distributed in nature, is con- 
tained in most natural waters, fresh or mineral. When the quantity of 
iron salts exceeds forty milligrams per litre, the water may be considered 
as having medicinal value. Chalybeate waters are usually cool, some- 
times warm, have a ferruginous taste, and are clear as they emerge from 
the earth. Those containing iron in the form of its bicarbonate become 
turbid and deposit a brownish yellow sediment on exposure to air, the 
bicarbonate being decomposed and carbon dioxide given off. Besides 
ferrous bicarbonate, many of the waters of this class contain ferrous sul- 
phate, crenate and apocrenate, calcium carbonate, sulphates of potassium, 
sodium, calcium, magnesium, and aluminium, notable quantities of sodium 
chloride, and sometimes arsenical compounds. 

Saline waters. — The solid constituents of waters of this class are so 
diverse in kind that the group may well be divided in subgroups. 

a. Chlorine waters are such as contain large quantities of sodium 
chloride, associated with less amounts of the chlorides of potassium, cal- 
cium, and magnesium. Some of these are so rich in sodium chloride that 
they are not of service as therapeutic agents, but are evaporated either 
by solar or artificial heat, to yield a more or less pure salt. Any natural 
water containing more than 3 grams per litre of sodium chloride belongs 
to this class, provided it do not contain substances more active in their 
medicinal action in such proportion as to warrant its classification else- 
where. Waters containing more than 15 grams per litre are too concen- 
trated for internal administration. They are usually cool, and have a salt, 
but not a bitter taste. Some of them are highly charged with carbon 
dioxide, and in some instances the pressure under which they are dis- 
charged from the earth is sufficient to project them to a height of over 
thirty feet. They contain also traces of iodides and bromides, and bicar- 
•bonates of sodium and calcium. 

p. Sulphate waters are actively purgative from the presence of consid- 
erable proportions of the sulphates of sodium, calcium, and magnesium. 
Some contain large quantities of sodium sulphate, with mere traces of the 
calcium and magnesium salts, while in others the proportion of the sul- 
phates of magnesium and calcium is as high as 30 grams per litre, to 20 
grams per litre of sodium sulphate. They vary much in concentration; 
from 5 grams of total solids to the litre in some, to near 60 grams per litre 
in others. They have a salty, bitter taste, and vary much in temperature. 

y. Bromine and iodine waters are such as contain the bromides or 
iodides of potassium, sodium, or magnesium in sufficient quantity to com- 
municate to them the medicinal properties of those salts. An exagge- 
rated type of this class is to be found in the water of the Dead Sea, 
which contains a large proportion of magnesium bromide. The mineral 
waters of Pomeroy, O., are worked as a source of bromine. 

Sulphurous toaters. — The waters of this class are distinguished by 
the presence of hydrogen sulphide or of the sulphides of the alkaline 
metals — usually of both. Their temperature varies much in different 
waters, but is usually high. They have the disagreeable odor of hydrogen 
sulphide, and form a black mixture with a solution of a lead salt. The 
fixed salts which they hold in solution are principally sodium chloride, 
sulphate, and bicarbonate, and calcium bicarbonate. The proportion 
of total solids varies in different waters of this class from 0.2 to 4 grams 
per litre. 



MINERAL WATERS. 



61 



COMPOSITION OF MINERAL WATERS. 



QUANTITIES IN MILLIGRAMS PEE LITRE. 





1. 


2. 


3. 


4. 


1 

: 5. 


: e. 


7. 


8. 


9 - 


10. 




00 

u 



to 
U 

k 


4a 

43 

(3 

a 

o 


6 

'•5 

c 
o 
a 


«5 
co 

s 

1 


.25 

H 

8 

< 




'u 

o 
-a 

> 


"3 

43 

'3. 
> 


03 

a 

4>J 
CG 

V 

•SB 

> 


CO ^_ 

£ 03 

II 

la 

5 




17.5° 


11° 


13° 


13.5° 


! 18.5° 


10.5° 


41.8° 


30.8° 








1.0034 
4070 


1.0018 
2091 


2193 


2457 





1.0031 
4345 


7006 


7155 


7195 






240 


Carbon dioxide. . . . 


1035 


1946 


1083 


2249 


• • • • 


2458 


908 


1067 


1049 


12.6 


Sodium bicarbonate 


979 


957 


166 


84 


1257* 


1049 


4883 


5029 


5103 


11 


Potassium ' ' 


.... 




• ■- • • 


• • • . 




59 


352 


440 


315 


1.3 


Lithium " 


.... 


20 


. . - . 


3 


• • • - 




.... 


• • • • 




.... 


Calcium " 


551 


431 


1359 


677 


59* 


577 


434 


570 


462 


38 


Strontium " 


traces. 




• . . . 


3 






3 


5 


5 




Barium " 


.... 





• • • * 


• . • • 







• • • • 


• • * • 






Magnesium *' 


209 


313 


35 


167 


442* 


405 


303 


200 


328 


6.7 


Ferrous ' ' 


30 


* * • • 


• - ♦ • 


5 





4 


4 


4 


4 


.... 


Manganous " 




* • • • 


• • a • 


2 




■ • » . 


traces. 


traces. 


traces. 


.... 


Sodium chloride . . 


2040 


71 


150 


1690 


466 


1267 


534 


518 


534 


6.7 


Potassium " 


1 


• • • • 


.... 


37 


• • • « 






.... 


.... 


.... 


Lithium " 


.... 


• • • • 


.... 


.... 


• • * ■ 






.... 


.... 


.... 


Calcium " 


.... 


• • • • 


.... 


.... 




.... 


• • • • 


.... 


.... 


.... 


Magnesium chloride 


.... 


• « . • 




.... 


.... 




• • • • 


.... 


.... 


.... 


Sodium sulphate . 


150 


23 


i75 


.... 


300 


972 


291 


291 


291 


92.7 


Potassium '* 


.... 


148 


• • • • 


23 







.... 


• • • • 


.... 


.... 


Magnesium " 


.... 




• • . • 


.... 


.... 


.... 


. • • • 


• • • • 




.... 


Calcium ' ' 


.... 




53 


• • • . 


• . • • 




.... 


.... 




.... 


Sodium phosphate. 


40 




.... 


1 


• • • • 


.... 


130 


46 


91 


.... 


Potassium ' ' 






.... 


• • * • 


« • • • 


■ • . • 


.... 


.... 


.... 


.... 


Calcium " 


.... 




.... 




• • • • 


• • • • 


.... 


.... 


.... 


.... 


Aluminium ' ' 


.... 




.... 


. . • • 




.... 




.... 


.... 


.... 


Sodium iodide 


.... 




• . . . 


• • • • 




i 




.... 


.... 


.... 


Potassium " 


t . . . . 




traces. 


■ ■ • • 




. . . . i 




.... 


.... 


.... 


Sodium bromide. . . 


traces. 




.... 


1 


• • • • 


1 


.... 


.... 


.... 


.... 


Potassium " ... 


.... 




.... 


• > • • 


• • • • 


• • • • ! 


i 
1 


.... 


.... 


.... 


Silex ) 


50 


j.... 
( 63 


.... 


'ioi 


"8 


"io 


! 

"70 


50 


m 

"ho\ 




Organic matter. . . . 


traces. 




.... 


.... 





.... 


traces. 


traces. 


traces. 


traces. 


Ferrous sulphate . . 


.... 




.... 


.... 




. . . . ! 


.... 




.... 


.... 


Ferrous crenate. . . . 







10 

I 


— 


... 


1 





....j 










>> 




>, 


03 




: 


























-w 








c 


s 


a 




<t-i 




o 


« 


<u 












a 


o 










u £ 




H 


o 
SO 


w 


0) 


o 

in 


U 

o 


o 


o 


O 1 

o 


.a o> 




o 


W 


o 


Ph 


m 


s 


a 


pq 


W 


>"5 



* Calculated as carbonates instead of bicarbonates. 

(1.) Sodium and calcium crenates, traces. (2.) Sodium borate, 65. (3.) Silicates of 
calcium and of aluminium, 245. (4.) Oxide of iron, 20. (5.) Alumina, strontia, lithia, 
organic matter — traces. (7, 8, and 9.) Sodium arsenate, 2; sodium borate, traces. (10.) 
Calcium fluoride, 9.2; sodium silicate, 57 ; lithium silicate, traces; baregine, traces. 



62 



GENERAL MEDICAL CHEMISTRY. 



COMPOSITION OF MINERAL WATERS— Continued. 





11. 


12. 


13. 


14. 


15. 


16. 


17. 


18. 


19. 


20. 




a 








'5' 

eS 














S3 
S3 

B 


(3 

g 




3 


TO 


'3 



02 


u 




eS 


Is 


c 

8 




8 


m 
to 


o 


■8 


O 


fi TO 


fe 


T3 
TO 


n f 3 






TO 




e3 


t>> 




TO =3 






-S 







TO ^ 


TO M 


3 


■+3 


rt 


~«2 

c3 — ' 


IB 


^3 


«Ph 

43 v ~' 


0J 




W&- 


H 


w 





pq 


! io° 


C!5 


pq 





g 




35.3° 


! 46.3° 






11.1° 




i 






Density 


1 0031 


1 0031 






1 0159 


; 1 015 












3543 


3518 


1405 


3803 


21138 


16906 


606 


612 




4628 


Carbon dioxide 


902 


884 


417 


* • . 


3627 


4580 


• • > • 


• • • • 




19 


Sodium bicarbonate 


2032 


1979 




1 658 


204 


82 


111 


22 






Potassium ' ' 






606 


m 9 


• • • 




• > • • 








Lithium " 


traces. 


traces. 


32 




133 


202 


• • • • 








■Calcium " 


233 


236 


214 


1157 


4082 


3311 


267 


292 


243* 


179* 


Strontium " 


0.28 


0.48 


.... 




15 


traces. 


• • • • 


• • • • 






Barium " 






25 




67 


31 










Magnesium " 


200 


187 




1086 


3096 


3104 


190 


212 


97* 


6.5* 


Ferrous " 


2.6 


3.6 


4.3 


• • • • 


27 


158 


2 


1 




10.3* 


Manganous ' ' 


0.8 


0.6 


• • • 


a • • • 


• • • • 




• • • • 


• • • • 






Sodium chloride. . . 


984 


1012 


70 


> • • • 


12855 


9809 


3 


20 


3420 


3089 


Potassium " ... 








traces. 


570 


97 








132 


Lithium " 










• • • • 










4 3 


Calcium il 






. . . . 




• • • • 






.... 




794 


Magnesium " 




m m 


■ > • • 


.... 


• . • • 




• • • • 


• • • 


114 


312 


Sodium sulphate. . . 


2.2 


0.8 




.... 


• • • . 


.... 


32 


9 


1354 




Potassium " ... 


39 


51 






9 






8 






Magnesium " 






12.7 





.... 












Calcium " ... 




. , . . 


472 


760 


.... 


• 










Sodium phosphate.. 






t • • * 


• « • • 






.... 


traces. 






Potassium ' ' 






■ • • • 


traces. 


.... 












Calcium " 






• • • • 





.... 


54 










Aluminium " 


6.4 


0.1 


* • • • 


• • • • 


.... 




• • * « 










traces. 


traces. 


• * .. • 





2 


11 


• • • • 






74 


Potassium " 










. . . , 




• • • • 








Sodium bromide. . . 




• • • 


.... 


m m 


62 


18 


• « • * 






10.7 


Potassium u 





• • « 


.... 


• ■ • ■ 






• • ■ 


% t 


.... 





Alumina 


.... 




"27 
traces. 


'l43 


1.3 
13 

traces. | 


trace. 
20 


•4 
16 

2 


2 

11 
34 


"38 

257 


traces. 


Silex 


1 


Organic matter. . . . 




Ferrous sulphate. . . 


.... 


• • * • 


.... 




. . 1 


. . • • 


.... 


• • * « 


.... 


.... 


Ferrous crenate. . . . 








! 





.... 





>> 











i 


"a 


TO 






jj> 


TO 

a 


>> 










<D 
























u 


o 


03 


xi 


U 


c3 


(3 




«w 




fe 


Ph 


EH 


S 





Ph 


rt 


pq 


<<P3 





* Calculated as carbonates instead of bicarbonates. 
(13.) Aluminium sulphate, 129 ; phosphoric acid and iodine, traces, 
chloride, trace. (20.) Ammonium chloride, trace; peroxide of iron, 15. 



(16.) Rubidium 



MINERAL WATERS. 



63 



COMPOSITION OF MINERAL WATERS— Continued. 



21. I 22. ! 23. 



£?§ 


B 


3 N 


n 


■°'M 


.Q 


Sw 


a 


o ~— 


o 


H 


H 


10° 


10° 



1.0015 1 012 

14175 14681 

2810 2399 



1431*, 1275* 



.5 <s 



24. I 25. ! 26. i 27. 



28. ! 29. 



be op 

S.§ 

go 



OS -^ 

be a 

SB 

a 
W 



<^ 


a 








o 








« 2 


eS 




bc5 


bo 


be « 


-S « 


O 


° 8 


°5 W 


03 

cs 


fa -^ 


02 


M2 


CO 



30. 



2(32* 

60*; 



6* 

51* 



10306! 10997 

.... 287 

ioiO 1238 
1014 781 
49.6 .. 



29 



traces, traces 

.... ... 

traces, traces 



41 



traces 
16 



11° 
1.0073 
8735 
1632 



1061 



17* 

31.6* 

traces. 

5882 
287 
200 



303 



587 
389 



5.6 

traces, j 
traces. I 

*8-4 



. ... 1.009 

7603 11662 15128 

3340 2914: 3252 

184' 155' 74 

..-.. ....I .... 

82! 36! 196 

2458! 1880' 2925 
traces, traces, traces. 



16 

2085 

6: 



1.3 



30: 



7.8 C 
1.011 

16995 8823 

3865' 2127 

1223, 257*; 

154 ]".'} 

2886 1319*: 

7 ...J 

35; .... 



. . . ! .... Temperature. 

. . .j ... .Density. 

837 j 66. Total solids. 

... .... j Carbon dioxide. 

. . . I 2* ! Sodium bicarbonate 

. . .j ... . jPotassium " 

. . . traces. Lithium ■ ' 

266 23* Calcium t; 

. . . j .... Strontium ' ' 

...! Barium " 



736 3025 l 2560 554* 



296 



5* .Magnesium 



14 1 



6864 ! 8684 
138! 74 



29 

8741 
165 



15 



2 
147 



traces, traces 
13 14 



47 
0.4 traces 



0.1 

4!e; 

7:2| 
20: 



2 



17: 55* 

96341 4953 

422! 



23 



traces. ! 



4 

26: 



4.3 
"38 



73 



2 traces. 



22 



11 



. . traces, traces 



traces. 



2 traces. (Ferrous " 
|Manganous - { 

32, 8 Sodium chloride, 

traces.: ... Potassium " 
Lithium " 
Calcium " 
Magnesium " 
99 . ...j Sodium sulphate. 
3 Potassium " 
. Magnesium k ' 
127! .... Calcium " 

Sodium phosphate. 
Potassium '' 
Calcium ' " 

Aluminium ' ' 
Sodium iodide. 
Potassium ' * 
Sodium bromide. 
Potassium ' ' 
4 traces. Alumina. 
6 18 Silex. 

3 5 Organic matter. 
.Ferrous sulphate. 
. Ferrous crenate. 



bo 

!3 



B 



* Calculated as carbonates instead of bicarbonates. 

(23.) Strontium sulphate, sodium borate, calcium fluoride, traces; sodium nitrate, 9.3; 
ammonia, 0.9. (24.) Calcium fluoride and sodium borate, traces. (25.) Calcium fluoride 
and sodium borate, traces. (26.) Calcium fluoride and sodium borate, traces. (27.) Cal- 
cium fluoride and sodium borate, traces. (28.) Potassium silicate, 120 ; sodium silicate, 
€9; strontium sulphate, trace. (30.) Calcium fluoride and lithia, traces. 



64 



GENERAL MEDICAL CHEMISTRY. 



COMPOSITION OF MINERAL WATERS— Continued. 



\ 31. 


32. 


■i). 


^ 


r— 


a 


p 


fl 


C 








Ul 


■s£ ! 




c « ! 




•EM 


A 


S 



Temperature 

Density 

Total solids 

Carbon dioxide. . . . 
Sodium bicarbonate 
Potassium " 
Lithium " 

Calcium " 

Strontium " 
Barium " 

Magnesium " 
Ferrous u 

Manganous " 
Sodium chloride 
Potassium ' k 
Lithium *' 
Calcium " 
Magnesium ' 4 
Sodium sulphate 
Potassium " 
Magnesium " 
Calcium ' ' 
Sodium phosphate. 
Potassium ' ' 
Calcium " 
Aluminium " 
Sodium iodide 
Potassium '* 
Sodium bromide 
Potassium " 

Alumina 

Silex 

Organic matter 
Ferrous sulphate 
Ferrous crenate. 



73° | 

.0047; 

5459 

788 
1262 



809 



1038 



12 ; 
1.007 
8653 

1154 

"q'.s\ 

3.6! 

1.7 

.... i 

463 J 
45.3' 

5 
1454 1 



2587; 4756 
..! 65 



0.22 2.4 
0.32' 7.1 



75 



traces 



W 



33. 34. 



Ph 



32440 

807' 



100 
834 



2260 
16120 

625 
12121 

338 



35. 



36. 


37. 


38. 


39. 


OS. 






"aT 


(3 








g3 
ha 

5 
>> 

a 


a 
o 


a 
c 

u 

.a 


3 

§ 

P. 

■aw 






V 


:C ~~^ 


W 


m 


w 


H 



40. 



.... 1.05241.003111.0118 

25294 57681 44879 14940 
402' .... .... .... 

434*! 1106*! .... 



15 i 700* 

i 
... 

52*6! '.'.'.'. 
153* 

7956 l 23i4| 



3939> 

6056,' 20828 17927 

198' 67 158 

5150i 25037 22422 

1346 6676 1512 



23 



traces 
traces 
traces 



by 



27 
151 



505 



1408 
12 

li612 

233 

28 

57 

1011 



4710 

506*! 

51 

25* 

3928 

'48 



....■ 57.5° 
4943 ! 7471 
2844* 



4j 98 
"u 

"id 

12 23 13 
, . . traces, traces, 



18* 
344* 



57* 
39* 



458 
110 



459 



■§■3 



« 



23 
60; 



330 
95 



98* 



5771 

381 
12£ 

879 



64 
*29 

12a 



ft 



aft 



* Calculated as carbonates instead of bicarbonates. 

(31.) Calcium fluoride, 3.2; ferric oxide, 3.6; manganese oxide, 0.8; magnesia, 179;. 
strontia, 0.96. (32.) Calcium fluoride, traces. (33.) Lithium sulphate, 0.4; strontium 
sulphate, 2.8; barium sulphate, 0.1. (34.) Magnesium bromide, 11. (38.) Peroxide of 
iron. 8. 



MINERAL WATERS. 



65 



COMPOSITION OF MINERAL WATERS— Continued. 



41. 


42. 


43. 


1 
| 44. 

1 


45. 


46. 


47. 


1 

4. 


49. 


50. 








"3 






















c 






s 






a 








,d 


n3 

93 




OS 

3 


a 
. 6 




3 


3 







i 

9 


c3 


a 

V 

bo 
o 


W 


bp3 

e3 w 


bCQ 

J3 03 
S 0Q 


+3 


B 

u 


a 

0J 
-H 

"3 


> — - 
•p 


-a 


fa 

o~-' 




O 


m 


ft 


ft 


OQ 


W 


ft 


O 


ft 


ft 






10.4° 


















Temperature. 




1.0007 


• • • • 




1.0073 


• • • • 


.... 


• » • • 




J Density. 


849 


603 


270 


5446 


6981 


14989 


2944 


4156 


1215 


801 Total solids. 


2471 


1920 


445 


traces. 


2316 






• • • 




38 Carbon dioxide. 




20.6 






264 












Sodium bicarbonate 






















Potassium " 






















Lithium " 


602* 


221 






1166* 


1076* 


855* 


159* 






Calcium " 






















Strontium " 






















Barium u 


74* 


212 


76 




801 




46* 








Magnesium " 


128* 


84 






96* 


146* 


70* 


66* 






Ferrous ' ' 


traces. 


18.4 








.... 


7* 








Manganous ' • 


6 


7 


12 


358 


4576 


11404 





2262 






7 Sodium chloride. 
. 'Potassium *' 






















Lithium " 












1523 




735 






Calcium " 






3 






761 


161 


484 






Magnesium " 





7.8 


6 




. .i 




306 




15 




Sodium sulphate. 




3.7 


.... 






25 


6 




12 




Potassium " 




• • • • 




597 






385 




216 


19 Magnesium '' 


21 


• • • 


40 


2344 




21 


1031 




86 


25 Calcium " 


..".'. 


traces. 




"407 


"35I 





"2 





"5 




.... 


Sodium phosphate. 
Potassium " 
Calcium " 
Aluminium " 
Sodium iodide. 




.... 










.... 




.... 


.... 


. . . .'Potassium " 
. . . .Sodium bromide. 
.., Potassium " 


traces. 


• • • « 


33 















252 Alumina. 


4 


32 


.... 


m 9 


35 


45 


71 


20 


29 


. Silex. 


. . • • 


traces. 


.... 


traces. 








40 


5 


Organic matter. 




• • • . 


.... 


607 








428 


11 


. .Ferrous sulphate. 








98 

















..... 


Ferrous crenate. 


.2 
3! 

bo 
o 


'2 

N 
U 


a 

(O 

H 


*-o1 

a> « cs 


m 

a 



a 

a 


be 
a> 


> 


a 
a 

a 

m 
O 


.5 
•3 

u 
as 


00 
<X> 

>> 

es 

w 

< 




ft 


ft 


o 


ft ft 


ft 


ft 


W 


w 


w 


A 





* Calculated as carbonates instead of bicarbonates. 

(43.) Crenates of sodium and potassium, 2. (44.) Alum, 407. (49.) Sulphates of 
copper, zinc, cobalt, and nickel, 4.11 ; ferric sulphate, 330; aluminium sulphate, 414 ; 
manganese sulphate, 3.29; lithium sulphate, 4.14; sulphuric acid (free), 68.85 ; magne- 
sium and ammonium nitrates, 8.82. 



66 GENERAL MEDICAL CHEMISTRY. 

COMPOSITION OF MINERAL WATERS— Continued. 





51. 


52. 


53. 


54. 


55. 


56. 


57. 


58. 


59. 


60. 




f 


u 

c 

t3 


0) 


CD 






3 


it 


*r 






a 


O 


"3 o 


"3> 'D 


. 




a 




p 


•» 




W 

00 

o 

a 

bo 


u 
© 

u 

a 
u 


««.2 

is 


53 CD 

i a 

AS 


o 
> 
a 


go 

"Sb 


a 

CD 02 


6 
O 

o b 

CD bo 


•B 

St'.B 

<D &D 


,B CS 

•g£ 




pq 


> 


<i 


3 


< 


£ 


M 


* 


* 


tf 




68° 




45.4° 


55° 


45° 










48° 


Density 




.... 


.... 


.... 


• • • • 


1.0317 


.... 


1.0065 


1.0025 


.... 




227 


267 


3730 


4102 


430 


3404 


372 


2578 


2314 


465 


Carbon dioxide. . . . 









• • • • 


26, 


• » • • 


.... 




92 


54 


Sodium bicarbonate 


traces. 


105* 


497* 


650* 


• • • • 


• • • ♦ 


.... 




• • • • 


• • « • 


Potassium k ' 




9.3* 










.... 




• • • • 


• • • • 


Lithium u 






0.29* 


0.29* 




• • • • 


0.27* 




to • ■ ■ 


• • • • 


Calcium " 




traces. 


132* 


158* 


148* 


83 


112* 




121* 


90* 


Strontium " 




i ■ • • 


traces. 


traces. 


traces. 


• • • • 


.... 




.... 


.... 


Barium ' ' 










• • • * 


• • • • 


• • • • 


.... 




.... 


.... 


Magnesium ' ' 




traces. 


25* 


51* 


26* 


• • • • 


100* 




.... 


83* 


Ferrous " 






6* 


10* 


9* 


8 


0.99* 




«... 


• . • • 


Manganous " 




» • • • 


■ • • • 


. . . . 


.... 


.... 


0.27* 




.... 


• . • • 


Sodium chloride. . . 


83 


15 


2465 


2639 


8 


1368 


4 


34 


.... 


.... 


Potassium " 






• * • • 


■ > • ■ 


• • • • 


8 


.... 




.... 


.... 


Lithium " 




■ • • a 


m 


• • • • 


• • • * 


• • • • 


.... 




.... 


.... 


Calcium * ' 








• • • • 




■ •> • • 


.... 




.... 


.... 


Magnesium " 




• • • • 


• • • • 


• • • • 


17 


513 


.... 




17 


.... 


Sodium sulphate. . . 


traces. 


18 


287 


283 


96 


60 


52 


io 


.... 


71 


Potassium " 


traces. 




107 


154 


• • • • 


# 


6 


33 


.... 


.... 


Magnesium u 










35 




• • • •' 


105 


607 


.... 


Calcium " 


traces. 


traces. 






16 


1041 


38 




1343 


10 


Sodium phosphate.. 




• • • • 


.... 


• • • • 


• • • • 


22 


.... 






.... 


Potassium ' ' 












• • • • 


.... 








Calcium " 








i • • 


. . . 


• • • • 


0.5 






.... 


Aluminium u 






traces. 


traces. 


traces. 


i ♦ • • 


.... 






. . . 




traces. 




• • * • 




traces. 


• • • • 


.... 






.... 


Potassium " 












* • • • 


.... 






.... 


Sodium bromide. . . 






4 


4 




• • • * 


.... 






.... 


Potassium ' k 








• • • • 




• • • • 


.... 






.... 


Alumina 




io 










0.11 






.... 


Silex 


44 


49 


00 


m 







14 


83 


27 


2 


Organic matter. . . . 


traces. 




93 


75 




• • • • 


13 


59 


75 


.... 


Ferrous sulphate. . . 




.... 


. . . • 


• • • • 




■ ■ • • 


.... 


1173 


.... 


.... 


Ferrous crenate. . . . 








.... 










... 








.... 






DO 


tc 


bo 


si 


si 


.5 


e! CD 


IE 

CD 

OS 

w 


DO 
CD 

» 




o 

.g 


B 


fit 
o 




0) 


>> 


o3 


S >> 
C3 c3 


< 


4 




u 


n 


Hi 


h? 


3 


a 


w 


Rfd 


< 


A 



* Calculated as carbonates instead of bicarbonates. 

(51.) Sodium sulphide. 78; ferrous and magnesium sulphides, traces; calcium silicate, 
22. (52.) Sodium sulphide, 41 ; oxides of iron and aluminium, 10. (53.) Sodium sulphide, 
19.5. (55.) Hydrogen sulphide, 26.8 c.c. ; aluminium sulphate, 54.8. (56.) Magnesium 
bromide, 12 ; sodium hyposulphite, 72 ; sodium sulphide, 24 ; silica and organic matter, 
192; hydrogen sulphide, 22.37 c.c. (57.) Copper carbonate, lead and barium sulphates, 
and arsenic, traces ; ammonium chloride, 0.3; strontium sulphate, 29; sodium hyposul- 
phite, 0.5; ammomum nitrate, 0.94; carbon dioxide, 53.7 c.c. ; hydrogen sulphide, 10.6 
c.c. (58.) Zinc sulphate, 333; ferric sulphate, 2880; aluminium sulphate, 1382; sulphu- 
ric acid (free), 97.36; phosphoric acid and ammonia, traces. (59.) Hydrogen sulphide, 
70.6 c.c. (60.) Hydrogen sulphide, 1.7 c.c. ; a peculiar sulphur compound, 144. 



HYDROGEN DIOXIDE. 67 

Physiological. — Water is taken into the economy both in its own 
form and as a constituent of every article of food. Under usual con- 
ditions, the amount taken by a healthy adult in twenty-four hours is 
2.25 to 2.75 litres, of which 1.75 to 2 litres are taken in the liquid form, 
the remainder forming a part of the solid food. 

The amount of water required by the system is greater when the 
amount eliminated by the skin and kidneys is increased, as during ex- 
posure to high temperature and in diabetes. When the food is dry the 
amount of water drank is increased. 

It constitutes about sixty per cent, of the weight of the body; in all 
of whose tissues and fluids it exists — most abundantly in the perspiration 
and saliva (99.5$), and least abundantly in the enamel of the teeth (0.2$). 
The proportion of water to solids in the body is greater in the earlier 
years of life: 

A fetal mouse contained 880 grams water in 1,000 grams. 

A newly born mouse contained 872 grams water in 1,000 grams. 

A mouse eight days old contained 768 grams water in 1,000 grams. 

A mouse full-grown contained 713 grams water in 1,000 grams. 

The consistency of the various parts does not depend entirely upon 
the relative proportion of solids and water, but is influenced by the nature 
of the solids. The blood, although liquid in the ordinary sense of the 
term, contains a less proportional amount of water than does the tissue 
of the kidneys, and about the same proportion as the tissue of the heart. 
Although the bile and mucus are not as fluid as the blood, they contain 
a larger proportion of water to solids than does that liquid. 

Water is discharged by the kidneys, intestine, skin, and pulmonary 
surfaces. The quantity discharged is greater than that ingested; the 
excess being formed in the body by the oxidation of the hydrogen of its 
organic constituents. 

Hydrogen Dioxide. 

Peroxide of Hydrogen — Oxygenated "Water — H 2 2 

Discovered by Thenard in 1818. It may be obtained in the pure state 
by accurately following a tedious process devised by Thenard. In a highly 
diluted form it is prepared by suspending pure hydrate of barium dioxide 
in water, through which a rapid current of carbon dioxide is then passed — ■ 

Ba0 3 H 9 +CO a =C0 3 Ba+H a O a , 

the insoluble barium carbonate being separated by filtration. 

Hydrogen dioxide is also formed in small quantities in the slow oxida- 
tion of metals, such as lead, zinc, cadmium, nickel, cobalt, and aluminium 
in damp air, as well as by the slow oxidation of phosphorus, and of 
many organic substances, essences, alcohol, ether, etc., and in the com- 
bustion of coal-gas. 

The pure substance is a colorless, syrupy liquid, which, when poured 
into water, sinks under it before mixing. It has a disagreeable, metallic 
taste, somewhat resembling that of tartar emetic. When taken into the 
mouth it produces a tingling sensation, increases the flow of saliva, and 
bleaches the tissues with which it comes in contact. It has a specific 
gravity of 1.455, and is still liquid at — 30°. It is very unstable, and, 
even in darkness and at ordinary temperatures, is gradually decomposed. 



68 GENERAL MEDICAL CHEMISTRY. 

At 20° the decomposition takes place more quickly, and at 100° rapidly 
and with effervescence. The dilute substance, however, is comparatively 
stable, and may be boiled and even distilled without suffering decom- 
position. 

This substance is subject to singular decompositions, acting both as 
a reducing and as an oxidizing agent. 

It is rapidly decomposed, with evolution of oxygen, by contact with 
gold or platinum in a state of minute subdivision, powdered charcoal, 
manganese dioxide, or fibrin — the decomposing agent remaining unaltered. 

Many elements and compounds, e. g., arsenic, sulphides, sulphur 
dioxide, are oxidized when brought in contact with hydrogen peroxide, at 
the expense of half its oxygen. 

If hydrogen peroxide be brought in contact with silver oxide, both are 
violently decomposed, with evolution of oxygen and liberation of heat 
and sometimes of li^ht. Water and metallic silver remain. 

The pure peroxide, when decomposed, yields 475 times its volume of 
oxygen; the dilute substance 15 to 20 times its volume. 

The presence of peroxide of hydrogen in very minute quantities may 
be detected by the following tests: 

First. — To a solution of starch a few drops of potassium iodide solu- 
tion are added, then a small quantity of the fluid to be tested, and 
finally a drop of a solution of ferrous sulphate; if hydrogen peroxide be 
present, a blue color is observed. This reaction may be obtained with a 
solution containing only 0.05 milligram per litre (Schoenbein). 

Second. — A mixture of tincture of guaiacum and extract of malt 
strikes a blue color in the presence of oxygenated water. Slightly less 
delicate than the last (Schoenbein). 

Other reactions have been proposed by Schoenbein, Barreswill, Striive, 
and Weltzien, which are, however, not characteristic. A colorimetrical 
method for determining the quantity of hydrogen peroxide has been pro- 
posed by Schone. 

Dilute oxygenated water is used for renovating old pictures the 
whites of which have become dingy by the formation of lead sulphide, 
which in the renovation is oxidized to the white sulphate. 

The various bleaching agents used to convert brunettes into blondes 
are dilute solutions of oxygenated water. 



HYDROGEN ELUOKLDE. 



69 



CLASS n. 

Elements all op whose Hydrates are Acids, and which do not 

form Salts with the Oxacids. 

I. CHLORINE GROUP. 

Fluorine F 19 

Chlorine CI , 35.5 

Bromine Br 80 

Iodine I 127 

The elements of this group are univalent. "With hydrogen they form 
acid compounds, composed of one volume of the element in the gaseous 
state with one volume of hydrogen. Their hydrates are monobasic acids 
when they exist (fluorine forms no hydrate). The first two are gases, 
the third liquid, the fourth solid at ordinary temperatures. Their atomic 
weights increase from the lowest to the highest by nearly 16 or 16x3. 
The relations of their compounds to each other are shown in the follow- 
ing table: 



HF, 
Hydroflu- 
oric acid. 





























HC1, 

Hydrochlor- 
ic acid. 


Cl 2 0, 

Chlorine 

monoxide. 


C1 2 3 , 
Chlorine 
trioxide. 


C1 2 4 , 
Chlorine 
tetroxide. 


C10H, 

Hypochlor- 

ons acid. 


C10 2 H, 

Chlorous 
acid. 


C10 3 H, 

Chloric 
acid. 


C10 4 H, 

Perchloric 
acid. 


HBr, 
Hydrobro- 
mic acid. 








BrOH, 

Hypobrom- 
ous acid. 




Br0 3 H, 

Bromic 
acid. 


Br0 4 H, 

Perbroinic 
acid. 










HI, 

Hydriodic 
acid. 






i 2 o 4 , 

Iodine 
tetroxide. 


IOH, 

Hypoiodous 

acid. 


I0 2 H, 

Iodous 
acid. 


I0 3 H, 
Iodic 
acid. 


I0 4 H, 

Periodic 

acid. 







FLUORINE. 

ForFl 19 

Although many attempts have been made to isolate this element, it 
has probably never been obtained in the free state, unless the colorless 
gas obtained by G. J. and Th. Knox, by the decomposition of mercury 
fluoride and of hydrofluoric acid in vessels of fluor-spar was the element. 
The difficulty in the way of its separation lies in the readiness with which 
it attacks the metals, as well as glass, porcelain, caoutchouc, etc. The 
source from which the compounds of fluorine are obtained is the natural 
calcium fluoride, or fluor-spar. 

Hydrogen Fluoride. 
Hydrofluoric Acid. 



HF1 



20 



First used for etching on glass, by Schwankhard, in 1670. Scheele, in 
1771, discovered the true nature of fluor-spar, and gave this acid the name 



70 GENERAL MEDICAL CHEMISTRY. 

of fluoric acid. Hydrofluoric acid is obtained by the action of an excess 
of sulphuric acid upon fluor-spar, with the aid of gentle heat: 

CaFl a -f- S0 4 H 2 = S0 4 Ca + 2HF1. 

If a solution be desired, the operation is conducted in a platinum or 
lead retort, whose beak is connected with a V-shaped receiver of the 
same metal, which is cooled and contains a small quantity of water. 

The aqueous acid is a colorless liquid, highly acid and corrosive, and 
having a penetrating odor. In using it great care must be exercised that 
neither the solution nor the gas come in contact with the skin, as they 
produce painful ulcers which heal with difficulty, and also constitutional 
symptoms which may last for days. When the acid has accidentally 
come in contact with the skin the part should be washed with dilute solu- 
tion of potash, and the vesicle which forms should be opened. 

Its boiling-point is between 15° and 30°. It is still liquid at — 40°, 
and has a specific gravity of 1.06. 

The most interesting chemical property of hydrofluoric acid is its ac- 
tion upon glass, from which it removes silica, a reaction which is utilized 
in the process of etching. For this purpose either the vapor or the solu- 
tion may be used. In either case the glass surface is coated with a var- 
nish composed of four parts of yellow wax and one part of turpentine, 
which is then removed from those parts upon which it is desired to act. 
When the solution is used a wall of wax is built up, and into the reservoir 
thus formed the liquid is poured; by this method a transparent design is 
produced. It is more usual to act upon the glass with the vapor, as by 
this means an opaque and consequently more apparent design is obtained. 
Some powdered fluor-spar is placed in a shallow leaden dish and moistened 
with sulphuric acid; the prepared glass plate is then placed, with the 
waxed surface downward, upon the dish, which is warmed to a tempera- 
ture not sufficiently elevated to melt the wax. 

The presence of fluorine in a compound is detected by reducing the 
substance to powder, moistening it with sulphuric acid in a platinum cru- 
cible, over which is placed a slip of glass prepared as above; at the end of 
half an hour the wax is removed from the glass, which will be found to 
be etched if the substance examined contained a fluoride. 

Fluorine forms no oxygenated compounds. 

CHLORINE. 
CI 35.5 

Although probably first obtained by Glauber, the discovery of this 
element is usually attributed to Scheele, who discovered it in 1774. 

Its true nature was first recognized by Sir Humphrey Davy in 1810. 
He gave it the name it bears, derived from ykoipos — yellowish green — in 
reference to its color. 

Preparation. — First. — By the process followed by Scheele, the action 
of manganese dioxide on hydrochloric acid, aided by heat: 

Mn0 2 + 4HC1 = MnCl 2 + 2H 2 + Cl a . 

The reaction is, however, not as simple as here indicated. Manganic 
chloride, MnCl 4 , is first formed and then decomposed into free chlorine and 
manganous chloride, MnCl 2 . Only half the chlorine contained in the acid 



CHLORINE. 71 

is liberated, and each kilo of manganese dioxide yields 257.5 litres c£ 
chlorine. 

Second. — By the action of manganese dioxide upon hydrochloric acid* 
in the presence of sulphuric acid: 

Mn0 2 + 2HC1 + S0 4 H 2 = S0 4 Mn + 2H a O + Cl a . 

The same quantity of chlorine is obtained as in first, with the use of 
one-half the quantity of hydrochloric acid. 

Third. — By double decomposition of sodium chloride and sulphuric 
acid, in the presence of manganese dioxide. A mixture of one part each 
of the two solids, finely powdered, is heated with three parts of sulphuric 
acid. In this process hydrochloric acid is first formed, according to the 
equation — 

S0 4 H 2 + 2NaCl = S0 4 Na 2 + 2HC1. 

The acid, as soon as found, is decomposed by either of the reactions 
indicated in first and second, according as sulphuric acid is or is not pres- 
ent in excess. 

Fou7'th. — By the action of potassium dichromate upon hydrochloric 
acid : 

Cr 2 7 K 2 + 14HCl=:2KCl+Cr 2 Cl 6 +7H 2 + 3Cl 2 . 

In this process, which is convenient, although not economical, 2 parts 
of powdered dichromate are heated with 11 parts of acid of sp. gr. 1.16; 
the generating flask being immersed in the water-bath. 100 grams of 
dichromate yield 22^- litres of chlorine. 

Fifth. — When a slow evolution of chlorine, extending over a con- 
siderable period of time, is desired, as for purposes of disinfection, moist- 
ened chloride of lime (see p. 412) is exposed to the air. The calcium 
hypochlorite is decomposed by the atmospheric carbon dioxide, with 
liberation of chlorine. If a more rapid evolution of gas be desired, the 
chloride of lime is moistened with a dilute acid in place of with water. 

Chlorine is, at the ordinary temperature and pressure, a greenish yel- 
low gas, has a penetrating odor, and is very irritating to the air-passages, 
even when highly diluted with air. Its specific gravity is 2.45 A. or 
35.5 H. A litre of chlorine at the normal temperature and pressure 
weighs 3.17 grams. It is quite soluble in water, one volume of which 
dissolves three volumes of chlorine at 10° C. It must therefor be col- 
lected by displacement of air, the disengagement-tube passing to the 
bottom of the collecting vessel, whose mouth is directed upward. 

A saturated solution of chlorine in water is used in the laboratory, 
where it is known as chlorine water y and medicinally under the names 
Aqua chlorinii [XT. $.), Liquor chlori (Br.). Good chlorine water bleaches, 
and does not redden blue litmus. 

At a pressure of 6 atmospheres at 0°, or at 8J atmospheres at 12°, 
chlorine assumes the form of an oily, yellow liquid, whose density is 1.33, 
and whose boiling-point is 33.6°. It has not yet been solidified. 

Chlorine unites directly with all elements except fluorine, oxygen, 
nitrogen, and carbon, and with these, fluorine possibly excepted, it is 
capable of combining indirectly. In many instances the direct union of 
chlorine with another element is attended by the liberation of light as 
well as of heat. 



72 GENERAL MEDICAL CHEMISTRY. 

At a red heat chlorine decomposes water readily, with the formation of 
hydrochloric acid and the liberation of oxygen : 

2H a O+2CI a =4HCl+0 9 . 

The same reaction takes place more slowly at ordinary temperatures, 
under the influence of sunlight, and for this reason chlorine water must 
be kept in bottles of yellow glass. 

Chlorine is an active bleaching and disinfecting agent in the presence 
of water. Its action in this respect is that of an indirect oxydant; it 
decomposes water, liberating oxygen, which then attacks the coloring 
or odorous organic matter. 

In many instances chlorine acts directly upon organic matters, a por- 
tion uniting with an equivalent number of atoms of hydrogen to form 
hydrochloric acid ; while another portion takes the place of the atoms of 
hydrogen thus displaced. Thus, with marsh-gas, hydrochloric* acid and 
methyl chloride are formed : 

CH 4 +Cl 9 -=CHjCl+HCL 

Chlorine is capable of forming a definite hydrate, having the com- 
position C1.5H 2 0, which is a yellowish green, crystalline substance, formed 
when chlorine is passed through chlorine water cooled to 2° — 3°, and is 
again decomposed when the temperature reaches 10°. 



Compounds of Chlorine. 
Hydrogen Chloride. 

Hydrochloric acid — Muriatic acid — Acidum muriaticum (U. S.) — 
Acidium hydrochloricum {Br.). — HC1. — Although known to the alchem- 
ists, in solution, as spirits of salt, hydrochloric acid exists in nature in 
small quantities only; in volcanic gases and in the gastric juice of the 
mammalia (p. 75). 

The source whence hydrochloric acid is obtained, either as an incidental 
product or by a special process, is sodium chloride. 

One of the steps of Leblanc's process for the manufacture of sodium 
carbonate is the decomposition of sodium chloride by sulphuric acid: 

2NaCl + S0 4 H 2 = S0 4 Na 2 + 2HC1. 

The acid, thus liberated, being very deleterious to both vegetable and 
animal life, is passed through suitably arranged towers, where it meets a 
descending stream of water, in which it is dissolved to form, after con- 
centration, the muriatic acid of commerce. As Leblanc's process is being 
gradually superseded by another in which hydrochloric acid is not lib- 
erated (see p. 398), the acid is now specially prepared by the same re- 
action. 

Hydrochloric acid is formed in a number of other reactions, none of 
which, however, has been utilized for its industrial production. One 
which is of theoretical interest, is by the direct union of its constituents: 
one volume of hvdroo-en and one of chlorine unite, under the influence of 
sunlight, to form two volumes of hydrochloric acid gas. 



HYDROGEN CHLORIDE. 



73 



Hydrochloric acid is a colorless gas, having" an acid reaction, an acid 
taste, a sharp, penetrating odor, and producing great irritation of any 
tissue with which it comes in contact. Its specific gravity is 1.264 A or 
30.5 H. A litre weighs, at 0° and 760 mm., 1.6352 grams. When sub- 
jected to a pressure of 40 atmospheres at 4°, gaseous hydrochloric acid 
assumes the liquid form. In contact with moist air it forms white clouds. 
It does not burn in air, nor does it support combustion. It is very solu- 
ble in water; one volume of water at 0° dissolving 480 volumes, and at 
the ordinary temperature 460 volumes. 

The muriatic or hydrochloric acids used in the arts and in pharmacy 
are solutions of the gas in water of different degrees of purity and con- 
centration. A pure, saturated solution in pure water is a clear, colorless 
liquid, has a strongly acid taste and reaction, a specific gravity of 1.2, 
and gives off white fumes when exposed to the air. Non-saturated solu- 
tions have lower specific gravities, according to the degree of concentra- 
tion. 



SPECIFIC GRAVITIES OF SOLUTIONS OF HYDROCHLORIC 

ACID {Tire). 



Specific 
gravity. 


Acid of sp. 
gr. 1. Sin 
100 pts. 


HCl in 100 
pts. 


Specific 
gravity. 


Acid of sp. 
gr. 1. Sin 
100 pts. 


HCl in 100 
pts. 


Specific 
gravity. 


Acid of sp. 
gr. 1. 2 in 
100 pts. 


HCl in 100 
pts. 


1.2000 


100 


40.777 


1.1349 


67 


27.321 


1.0657 


33 


13.094 


1.1982 


99 


40.369 


1.1328 


66 


26.913 


1.0637 


32 


12.597 


1.1964 


98 


39.961 


1.1308 


65 


26.508 


1.0617 


31 


12.300 


1.1946 


97 


39.554 


1.1287 


64 


26.098 


1.0597 


30 


11.903 


1.1928 


96 


39.146 


1.1267 


63 


25.690 


1.0577 


29 


11.506 


1.1910 


95 


38.738 


1.1247 


62 


25.282 


1.0557 


28 


11.109 


1.1893 


94 


38.330 


1.1226 


61 


24.874 


1.0537 


27 


10.712 


1.1875 


93 


37.923 


1.1206 


60 


24.466 


1.0517 


26 


10.316 


1.1857 


92 


37.516 


1.1185 


59 


24.058 


1.0497 


25 


9.919 


1.1846 


91 


37.108 


1.1164 


58 


23.650 


1.0477 


24 


9.522 


1.1822 


90 


36.700 


1.1143 


57 


23.242 


1.0457 


23 


9.126 


1.1802 


89 


36.292 


1.1123 


56 


22.834 


1.0437 


22 


8.729 


1.1782 


88 


35.884 


1.1102 


55 


22.426 


1.0417 


21 


8.332 


1.1762 


87 


35.476 


1.1082 


54 


22 019 


1.0397 


20 


7.935 


1.1741 


86 


35.068 


1.1061 


53 


21.611 


1.0377 


19 


7.5?8 


1.1721 


85 


34.660 


1.1041 


52 


21.203 


1.0357 


18 


7.141 


1.1701 


84 


34.252 


1.1020 


51 


20.796 


1.0337 


17 


6.745 


1.1681 


83 


33.845 


1.1000 


50 


20.388 


1.0318 


16 


6.348 


1.1661 


82 


33.437 


1.0980 


49 


19.980 


1.0308 


15 


5.951 


1.1641 


81 


33.029 


1.0960 


48 


19.572 


1.0279 


14 


5.554 


1.1620 


80 


32.621 


1.0939 


47 


19.165 


1.0259 


13 


5.158 


1.1599 


79 


32.213 


1.0919 


46 


18.757 


1.0239 


12 


4.762 


1.1578 


78 


31.805 


1.0899 


45 


18.340 


1.0220 


11 


4.365 


1.1557 


77 


31.398 


1.0879 


44 


17.941 


1.0200 


10 


3.998 


1.1536 


76 


30.990 


1.0859 


43 


17.534 


1.0180 


9 


3.571 


1.1515 


75 


30.582 


1.0838 


42 


17.126 


1.0160 


8 


3.174 


1.1494 


74 


30.174 


1.0818 


41 


16.718 


1.0140 


7 


2.778 


1.1473 


73 


29.767 


1.0798 


40 


16.310 


1.0120 


6 


2.381 


1.1452 


72 


29.359 


1.0778 


39 


15.902 


1.0110 


5 


1.984 


1.1431 


71 


28.951 


1.0758 


38 


15.494 


1.0080 


4 


1.588 


1.1410 


70 


28.544 


1.0738 


37 


15.087 


1.0060 


3 


1.191 


1.1389 


69 


28.136 


1.0718 


36 


14.679 


1.0040 


2 


0.795 


1.1369 


68 


27.728 


1.0697 
1.0677 


35 
34 


14.271 
13.863 


1.0020 


1 


0.397 



74 GENERAL MEDICAL CHEMISTRY. 

The boiling-point of hydrochloric acid solution varies with the con- 
centration. It is the highest, 111.11°, with an acid of sp. gr. 1.094. 
When concentrated hydrochloric acid is boiled, the totality of the gas 
is not expelled; when it reaches the composition of the hydrate HC1, 
8H 2 0, nearly corresponding to the specific gravity given above, its boiling- 
point remains stationary and an acid of the same composition distils 
over. 

The varieties of the acid solutions used in the arts and in medicine 
are : 

Commercial muriatic acid, a yellow liquid; specific gravity about 
1.1G; contaminated with iron, with chloride of sodium, and with arsenical 
compounds. It is used only for manufacturing and coarse chemical pro- 
cesses. 

C. P. hydrochloric acid, a colorless liquid, usually far from pure 
(see below). 

Acidum muriaticum ( XT. S.) — Acidum hydrochloricum. (2?r.), a 
colorless liquid, of sp. gr. 1.16 = 32.3^ of the gaseous acid, which contains 
small quantities of impurities. 

Acidum muriaticum dilutum ( XT. S.) — Acidum hydrochloricum dil. 
(_Z?/\). — The last, diluted with water to sp. gr. 1.038, U. S. (1.052, Br.), and 
containing 7.74 per cent. HC1. (10.6 per cent., Br.). 

Hydrochloric acid is ranked, with nitric and sulphuric acids, as one of 
the strong mineral acids. It is decomposed by many metals, with liber- 
ation of hydrogen and formation of a chloride: 

2HCl+Zn=ZnCl 2 + H 2 . 

With oxides and hydrates it enters into double decomposition, form- 
ing water and a chloride: 

CaO + 2HC1 = CaCl 2 + H 2 0. 

CaH 2 2 + 2HC1= CaCl 2 + 2H 2 0. 

Most of the metallic chlorides are readily soluble in water, mercurous, 
silver, and lead chlorides being exceptions. 

By the action of oxidizing agents, hydrochloric acid is decomposed 
with liberation of chlorine, as in the reaction between it and potassium 
dichromate (p. 71). The chlorine, being thus in the nascent state, is 
capable of uniting with gold or platinum to form chlorides of those me- 
tals. The same liberation of chlorine takes place in the mixture of nitric 
and hydrochloric acids, in the proportion of one molecule of the former 
to three of the latter, known as Aqua regia, Acid, nitro-muriaticum 
{IT, $.), Acid, nitro-hydrochloricum (JBr.). 

Compounds formed by the substitution of a metal or radical for the 
hydrogen of hydrochloric acid are called chlorides. 

Analytical. — The presence of hydrochloric acid, or of a chloride in 
solution, may be detected by the formation of a white, flocculent pre- 
cipitate with silver nitrate, which is soluble in ammonia, but insoluble 
in nitric acid (see p. 81). 

Impurities. — Hydrochloric acid should be perfectly colorless. It 
should give no coloration with potassium sulphocyanate (iron). When 
shaken with chloroform, the latter should not be colored (bromine and 
iodine). It should not precipitate with solution of barium chloride, in 



HYDROGEN CHLORIDE. 75 

solution of sulphur dioxide (chlorine). It should give no reaction when 
tested for arsenic by Otto's method.* 

Physiological. — The existence of free hydrochloric acid in the gastric 
juice was first noted by Prout in 1824, and proved by Schmidt in 1852. 
Although Lehmann, Blondlot, Bernard and others have thought other- 
wise, subsequent investigations have fully confirmed the results of 
Schmidt. 

Toxicology. — Notwithstanding the frequent use of this acid in the 
arts, it is very rarely administered with murderous intent, owing to its 
pronounced odor and taste. Several cases are recorded, however, in 
which it has been taken either by accident, or with suicidal intent. Its 
action is similar to that of sulphuric acid (q. v.), but not as intense, ex- 
cept in so far as the larynx is concerned. The treatment consists in neu- 
tralizing the acid as quickly as possible by the administration of an alkali, 
or of magnesia. 

The detection of the acid in the body after death requires a quanti- 
tative determination. Stains produced by the acid upon colored cloth 
are of a brighter red than those produced by sulphuric acid, and do not 
destroy the fibre of the cloth to so great an extent. They disappear 
when moistened with aqua ammoniae, if they be not too old. 

Distinction between poisons and corrosives. — Although the delete- 
rious action exerted by certain substances when they are taken into 
the stomach in small quantities has been known and made use of by the 
evilly inclined from the earliest antiquity, the definition of a poison has 
been difficult. The element of quantity, although it is an important 
factor in the method of action of deleterious substances, does not afford 
ground upon which to base the desired definition, as it is impossible to 
fix definitely the dose of any poison which is necessarily lethal. Almost 
all substances, if taken in sufficient quantity, produce derangements 
which may terminate in death. 

There is this distinction between the methods of action of true poisons 
and of corrosives, such as the mineral acids : the former do not reveal 
their lethal character until they have been absorbed into the circulation / 
the latter act, not through the blood, but by coming into immediate con- 
tact with and destroying some organ essential to life. Sulphuric acid 
will destroy life as surely by disintegrating a large surface of skin as it 
will by corroding the coats of the stomach. Both actions are due to the 
same quality of the acid, y,et, if we include sulphuric acid among the 
poisons, we are forced to the unphilosophical conclusion of considering it 
a poison when it destroys the stomach, but not when it corrodes another 
equally essential organ. 

The best definition of a poison we believe to be the following : Any 
substance which, after absorption into the blood, produces death or serious 
bodily harm. The question of quantity is thus avoided, and, according 
to our definition, as in accordance with fact, the same substance is or is 
not a poison, as it is taken in quantities sufficient or insufficient to pro- 
duce harmful results. 

The mineral acids and alkalies, acting' at their points of immediate 
contact with the tissues, find a place medically and toxicologically under 
the head of corrosives, and legally among the " other noxious or destruc- 
tive things " mentioned in statutes relating to poisoning. 

* Ausmittel d. Gifte, 5th ed., p. 97, note. 



76 GENERAL MEDICAL CHEMISTRY. 



Compounds of Chlorine and Oxygen. 

Three compounds of chlorine and oxygen have been isolated, two 
being anhydrides. They are all very unstable, and prone to sudden and 
violent decomposition. 

Chlorine monoxide, C\fi=hypochlorous anhydride or oxide, is ob- 
tained by the action of dry chlorine upon cooled, precipitated mercuric 
oxide — 

HgO + 2Cl 2 =HgCl 2 + Cl 2 0, 

as a blood-red, mobile liquid below 20°. Above that temperature it is a 
reddish yellow gas, having a penetrating odor similar to that of chlorine. 
It is decomposed with an explosion upon the slightest jar, and even 
spontaneously. When brought into contact with water it slowly forms a 
nearly colorless solution, containing hypochlorous acid, ClOH, which may 
be more readily obtained in solution by passing a current of chlorine 
through water holding recently precipitated calcium carbonate in sus- 
pension, and subjecting the solution to distillation, the receiver being 
well cooled. 

This solution is a yellow liquid, having an acrid taste and an odor of 
chlorine. It is an exceedingly active oxidizing and bleaching agent. 
Owing to its instability, the acid itself is not used industrially, although 
its salts, the hypochlorites of calcium, potassium and sodium are (see 
pp. 412, 401, 398). 

Chlorine trioxide, C1 2 3 = chlorous anhydride or oxide, is obtained 
by the action of dilute nitric acid upon potassium chlorate, in the pres- 
ence of arsenic trioxide. It is a greenish yellow gas ; decomposes at 
about 50° C, with explosion; soluble in water; has strong bleaching 
powers, and an irritating action upon the air-passages w T hen inhaled. Its 
aqueous solution contains chlorous acid, C10 2 H — a very unstable body, 
which has not been isolated, corresponding to a series of salts called 
chlorites. 

Chlorine tetroxide, C1 2 4 = chlorine peroxide, a violently explosive 
body, obtained by the action of concentrated sulphuric acid upon potas- 
sium chlorate. Below — 20° it is an orange-red liquid, and above that 
temperature a yellow gas, probably composed of C1 2 + C1 2 0. Although 
this body is sometimes improperly called hypochloric acid, there is no 
corresponding hydrate; and if it be brought in contact with an alkaline 
hydrate, a mixture of the chlorate and chlorite of the metal is formed: 

C1 2 4 + 2KHO = C10 3 K + C10 3 K + H 2 0. 

Besides the above, there exist two other oxacids of chlorine, whose cor- 
responding anhydrides have not been isolated. These are chloric and 
perchloric acids. 

Chloric acid, C10 3 H — obtained in aqueous solution, by decomposing 
its barium salt with the proper quantity of dilute sulphuric acid. As 
thus obtained, it is a syrupy liquid, colorless or yellowish, and strongly 
acid. It decomposes at 40°, and is an energetic oxydant. 

Perchloric acid, C10 4 H — the most stable of the series, is prepared by 
boiling potassium chlorate with hydrofluosilicic acid, cooling, decanting 
the clear fluid, which is evaporated and from time to time decanted until 



HYDROGEN BROMIDE. 77 

white fumes appear, when it is distilled. It is a colorless, oily liquid, 
sp. gr. 1.782; explodes on contact with organic substances or charcoal; 
corrodes animal tissues energetically. 

It enters into the composition of chlorodyne. 



BROMINE. 
Br 80 

Discovered by Balard in 1826. Its name is derived from /3poj^of, an 
evil odor. It does not exist free in nature, but is found in combination 
with the alkaline metals and magnesium, widely diffused, but in small 
quantities. 

It is obtained from the mother-liquors of salt springs, especially those 
of Stassfurth and Kreuznach in Germany, and of Pomeroy, Ohio; from 
the mother-liquor left in the manufacture of sea-salt; and from kelp (see 
p. 78). These are subjected to distillation with manganese dioxide and 
sulphuric acid, by which the bromides are decomposed and elementary bro- 
mine liberated. 

At ordinary temperatures, bromine is a dark, reddish brown liquid; 
has a strong, disagreeable odor, somewhat resembling that of chlorine ; 
is irritating to the air-passages, and corrodes animal tissues with which 
it comes in contact. 

It is volatile at all temperatures above its point of solidification, 
giving off red fumes. It boils at 63°. Its freezing-point is variously 
given from — 7.3° to — 24.5°. The latter is probably the correct one, the 
higher freezing-points of some samples being due to the presence of 
water. Sp. gr. 3.1872 at 0°. Soluble in water to the extent of 3.2 parts 
in 100 at 15°. When the solution is cooled to 0° in the presence of an 
excess of bromine, a crystalline hydrate, Br.5H 2 0, is formed. It is more 
soluble in alcohol, carbon disulphide, chloroform, and ether, than in water. 
Its solutions, which are yellow or brown, according to concentration, are 
decomposed by exposure to light, with formation of hydrobromic acid. 

Its chemical properties are the same as those of chlorine in kind, but 
less energetic. 

It is highly poisonous, but, owing to its comparative rarity and its 
powerful odor, only one case of death from its action has been recorded. 

Free bromine may be recognized by its odor, by the yellow or brown 
color of its chloroform solution, and by the yellow or orange color which 
it communicates to starch paste. (For the analytical reactions of the 
bromides, see p. 81.) 



Hydrogen Bromide. 

Hydrobromic acid, HBr. — This acid cannot be obtained by decom- 
position of a bromide as hydrochloric acid is obtained by decomposition 
of a chloride, as it is destroyed by the presence of any excess of sulphuric 
acid. It is obtained by the action of water upon phosphorus tribromide — ■ 

PBr 3 + 3H 2 0=P0 3 H 3 + 3HBr, 

or by the action of bromine upon paraffine. 

It is a colorless gas; produces white clouds on contact with air; li- 
quefies at —69°, and solidifies at —73°; has an acid taste and reaction, and 



78 GENERAL MEDICAL CHEMISTRY. 

dissolves readily in water, with which it forms a definite hydrate, HBr 
2H 2 0. Its chemical properties are similar to those of the corresponding 
chlorine compound. Its hydrogen is replaceable by metals to form 
bromides. 

Oxacids of Bromine. 

No oxides of bromine are known, although three oxacids exist, either 
in the free state or as salts: 

Hypobromous acid — BrOH — may be obtained, in aqueous solution, 
by the action of bromine upon mercuric oxide, silver oxide, or silver ni- 
trate. When bromine is added to concentrated solution of potassium 
hydrate, no hypobromite is found, but a mixture of bromate and bromide, 
having no decolorizing action. With sodium hydrate, however, sodium 
hypobromite is formed in solution, and such a solution, freshly prepared, 
is used in Knop's process for determining urea (p. 264). 

Bromic acid — Br0 3 H — is readily obtained, in aqueous solution, by 
the action of chlorine upon bromine, in the presence of water, or by the 
decomposition of barium bromate, suspended in water, by sulphuric acid. 
In combination as a bromate, it is obtained by the action of bromine 
upon a solution of potassium hydrate — 

6KHO + 3Br 2 = Br0 3 K + 5KBr + 3H 2 0, . 

the bromate being separated from the bromide by taking advantage of its 
more sparing solubility. 

Perbromic acid — Br0 4 H — is obtained as a comparatively stable, oily 
liquid, by the decomposition of perchloric acid by bromine, and concen- 
trating over the water-bath. It is noticeable in this connection that, 
while hydrochloric acid and the chlorides are more stable than the corre- 
sponding bromine compounds, the oxygen compounds of bromine are more 
permanent than those of chlorine. 



IODINE. 

,.; 127 



Discovered in 1811 by Courtois; further studied by Gay-Lussac in 
1814, and by Sir H. Davy at about the same time. Name derived from 
tcoSi7<?, violet, referring to the color of its vapor. 

Iodine has not been found to exist in nature in the free state, but in 
combination it is widely disseminated in the three kingdoms of nature, 
without, however, being anywhere abundant. The iodides of potassium, 
sodium, calcium, and magnesium exist in small quantities in sea-water, in 
the waters of mineral springs, and indeed, in mere traces, in most natural 
waters; more abundantly in the ashes of marine plants, sponges, molluscs 
and polyps, as well as in the bodies of animals living in salt water. Cod- 
liver oil contains appreciable quantities of iodine — according to De Jongh, 
37 parts in 100,000. 

Iodine is obtained almost exclusively from the ashes of sea-weeds 
collected in Scotland and in the north of France. The weeds are burned, 
and the ash, known as help in Scotland, and as varech in France, is ex- 
tracted with water, and the solution subjected to fractional crystalliza- 



IODINE. 79 

tion. The last concentrated mother-liquid, which refuses to crystallize, 
contains the iodides; they are decomposed by a current of chlorine, aided 
by heat; the iodine being thus driven off, is collected in suitable con- 
densingr-chambers. 

It occurs in iron-gray, brittle, crystalline scales, having a metallic 
lustre, and a sp. gr. of 4.948 at 17°. It melts at 113.6° and boils at 175°. 
Its vapor is of a rich violet color. It volatilizes at all temperatures, the 
vapor condensing in the crystalline form. The density of the vapor is 
8.716 A, or 127 H. It has a peculiar and characteristic odor, and a disa- 
greeable taste; is sparingly soluble in water, which takes up a larger 
quantity, however, on standing over an excess of iodine — owing to the 
formation of hydriodic acid, in a solution of which iodine is more soluble 
than in pure water. The solubility of iodine is very much increased by 
the presence of certain salts, notably of potassium iodide. A solution of 
iodine in solution of potassium iodide is used in medicine, under the 
names Liq. iodinii compositus {U. $.), Liq. iodi (Lr.), LitgoVs solution. 
Iodine is soluble in alcohol (Tinct. iodinii), and in ether with a brown 
color; in chloroform, benzol, and carbon disulphide, with a violet color. 

Its chemical properties are similar to those of chlorine and bromine, 
but less marked. In the presence of water, iodine exerts a slight oxidiz- 
ing and decolorizing action. It decomposes hydrogen sulphide with lib- 
eration of elementary sulphur and formation of hydrogen iodide. It does 
not combine with ordinary oxygen, but does with ozone. It unites directly 
with many of the metalloids, and with most of the metals, to form iodides. 
It dissolves in solution of potassium hydrate, with formation of potassium 
iodide and some hypoiodide. Nitric acid oxidizes it to iodic acid. With 
ammonium hydrate it forms nitrogen iodide (q. v.). 

Free iodine may be detected by the blue-violet color which it com- 
municates to starch, and by the violet color of its solutions in carbon 
disulphide and chloroform. 

Commercial iodine is liable to contamination with foreign substances. 
Of these, non-volatile bodies, such as manganese dioxide, graphite, etc., 
may be detected and separated by subliming the iodine. Water has been 
found to be used as an adulterant of iodine in as large quantity as twenty 
per cent.; it renders the iodine moist and sticky; and when iodine so 
adulterated is dissolved in carbon disulphide, the water separates in a dis- 
tinct layer. Chlorides of calcium and magnesium have also been detected 
in iodine. The most serious contamination, however, is that with the 
iodide of cyanogen, which is probably formed during the process of manu- 
facture, by the decomposition of cyanides contained in the kelp. The 
scales of iodine so contaminated have upon their surfaces minute, white, 
acicular crystals. To detect and at the same time separate this impurity 
when present even in very small quantities, heat one ounce of the iodine 
over the water-bath in a porcelain dish, covered by a flat-bottomed flask 
containing cold water. After about twenty minutes' heating the iodide 
of cyanogen will have collected on the bottom of the flask, in white acicu- 
lar crystals. 

Action on the Economy. 

When brought in contact with the skin it produces irritation and a 
brown stain, which, however, soon disappears. When taken internally, 
it acts both as a local irritant to the surfaces of the intestinal canal, with 
which it comes in contact, and as a true poison. Cases of acute iodine 



80 GENERAL MEDICAL CHEMISTRY. 

poisoning are not common, and those recorded are due to accident or neg- 
ligence, with one exception, in which homicide was prevented by the 
color communicated to the starchy fluid with which the iodine was mixed. 
It is probable that when iodine is administered internally, it is converted 
into hydriodic acid (q. v.) during the processes of assimilation. At all 
events, it is ultimately discharged as an alkaline iodide by the urine and 
saliva, but not by the perspiration, whether it be taken as free iodine or 
as potassium iodide; when taken in large quantities, it also appears in 
the fceces. The treatment consists in removing the poison by emetics or 
the stomach-pump, as rapidly as possible. 



Hydrogen Iodide. 

Hydriodic acid — HI. — Hydriodic acid does not exist in nature. For 
its preparation recourse is had to the decomposition of phosphorus tri- 
iodide by water: 

PI 8 -f3H a O=P0 3 H 8 +3HI. 

Red phosphorus is placed in a retort, under water ; the proper quantity 
of iodine is then added and the retort heated. 

When desired in solution, it is more readily obtained by directing a 
current of hydrogen sulphide through water holding iodine in suspension — 

H 2 S + I 2 =2HI+S, 

and filtering from the precipitated sulphur. This is the method directed 
by the U. S. P. 

Hydrogen iodide is a colorless gas, fuming on contact with air, having 
a strong acid reaction and a penetrating odor. Sp. gr. 4.443 A — 64.2 H. 
By cold and pressure it maybe condensed to a yellow liquid", which solidi- 
fies at — 55°. It is very soluble in water, one volume of which, at 10°, 
dissolves 425 volumes of the gas. The saturated solution has a density 
of 1.7. When heated, like hydrochloric acid solution, it gives off a part 
of its gas, until the boiling-point becomes stationary at 126°, when the 
remainder distils without decomposition. 

Hydriodic acid is decomposed into its component elements when 
heated — the decomposition being only partial, as the same influence 
brings about a partial union of the elements. When a mixture of hydriodic 
acid and oxygen is ignited, iodine is set free and water is formed. The 
same action takes place when the mixture is exposed to sunlight. 
Aqueous solutions of hydriodic acid, when exposed to the light, quickly 
become brown from a decomposition of the acid, with separation of ele- 
mentary iodine. Hydriodic acid is also decomposed by a number of other 
substances ; by many metals with formation of metallic iodides and 
liberation of hydrogen; by chlorine and bromine with liberation of iodine; 
by sulphuric and nitric acids, also with liberation of iodine; and by many 
chlorides, with formation of hydrochloric acid and an iodide: 

PC1 3 +3HI=:PI 3 + 3HC1. 

The readiness with which it gives up its hydrogen renders it a valuable 
source of that element in the nascent state, for which purpose it is used 
in organic chemistry. 



OXACIDS OF IODINE. 81 

In aqueous solution it is officinal in the U. S. P. as Acid, hydriodicum 
dil., which, however, is very prone to decomposition. 



Analytical Characters. 

Chlorides, bromides, and iodides. — The detection and determination 
of any one of these classes of compounds is simple in the absence of the 
other two. When it is uncertain, as is usually the case, whether there 
be not two or more of them present, the determination becomes more 
difficult. Silver nitrate forms a precipitate with either of the three, 
which is white, or yellowish if the bromide or iodide be present in large 
quantity, and is insoluble in dilute nitric acid. Ammonium hydrate dis- 
solves the precipitate very readily in the case of the chloride, much less 
readily in that of the bromide, and with great difficulty in that of the 
iodide. 

The best means of distinguishing between the three is by adding a 
few drops of carbon disulphide and chlorine water; upon shaking the 
mixture the disulphide is colored violet in the presence of an iodide, 
yellow or orange by bromine, and remains colorless if neither bromide 
nor iodide be present. 

Cyanides also give a white precipitate with silver nitrate, insoluble in 
dilute nitric acid and rather soluble in ammonium hydrate ; they are 
detected by the characters given on p. 340. 

For the methods of detecting small quantities of these salts in the 
presence of each other, and for their estimation, see the works of Rose, 
Fresenius, and Gerhard and Chancel. 



Oxacids of Iodine. 

The best known of these are the highest two of the series — iodic and 
periodic acids. 

Iodic acid — I0 3 H — does not exist in nature. It is formed as an 
iodate, whenever iodine is dissolved in a solution of an alkaline hydrate — 

I 6 + 6KHO = I0 3 K + 5KI + 3H 2 0, 

as the free acid, by the action of strong oxidizing agents, such as nitric 
acid or chloric acid, upon iodine; or by passing chlorine for some time 
through water holding iodine in suspension. The preparation and puri- 
fication of iodic acid are always tedious. 

Iodic acid appears in white crystals, decomposable at 170°, and quite 
soluble in water, the solution having an acid reaction, and a bitter, as- 
tringent taste. 

It is an energetic oxidizing agent, yielding up its oxygen readily, with 
separation of elementary iodine or of hydriodic acid. It is used as a test 
for the presence of morphine (q. v.). 

Periodic acid / I0 4 H — is formed by the action of chlorine upon an 
alkaline solution of sodium iodate. The sodium salt thus obtained is dis- 
solved in nitric acid, treated with silver nitrate, and the resulting silver 
periodate decomposed with water. From the solution the acid is ob- 
tained in colorless crystals, fusible at 130°, very soluble in water, and 
readily decomposable by heat. 
6 



82 



GENERAL MEDICAL CHEMISTKY. 



II. SULPHUR GROUP. 

Sulphur S 32 

Selenium Se 79.5 

Tellurium Te 128 

The elements of this group are divalent. With hydrogen they form 
compounds composed of one volume of the element, in the form of vapor, 
with two volumes of hydrogen — the combination being attended with a 
condensation in volume of one-third. Their hydrates are dibasic acids. 
They are all solid at ordinary temperatures. The relation of their com- 
pounds to each other are shown in the following table: 



H 2 S, 
Hydrogen 
sulphide. 


so 2 , 

Sulphur 
dioxide. 




so 3 , 

Sulphur 
trioxide. 


S0 2 H 2 , 

Hyposulphu- 

rous acid. 




S0 3 H 2 , 

Sulphurous 

acid. 


S0 4 H 2 , 

Sulphuric 

acid. 


H 2 Se, 

Hydrogen 

selenide. 


Se0 2 , 

Selenium 

dioxide. 




Se0 3 , 
Selenium 
trioxide. 






Se0 3 H 2 , 

Selenious 

acid. 


Se0 4 H 2 , 

Selenic 

acid. 




H 2 Te, 
Hydrogen 
telluride. 


Te0 2 , 

Tellurium 

dioxide. 




TeO s , 

Tellurium 

trioxide. 






Te0 3 H 2 , 

Tellurous 

acid. 


Te0 4 H 2 , 

Telluric 

acid. 










SULPHUR. 












s. 






32 







This element has been known in its own form from remote antiquity. 
It was called Oeiov by the Greeks. It occurs in actively volcanic regions, 
in crystalline powder, in large crystals, or amorphous. It is brought 
principally from Sicily, Iceland, and the vicinity of Naples, where it is 
found near " solfatarse," which are vents in the craters of extinct vo] canoes, 
through which gases still issue. 

The native sulphur is always accompanied by more or less earthy 
matter, from which it is separated by two distillations: one in the locality 
where it is collected, the product of which is crude sulphur/ and a 
second, in a more perfect apparatus, which yields refined sulphur. This 
is in one of two forms. During the first portion of the distillation, while 
the air of the condensing-chamber is still cool, the vapor of sulphur is 
condensed in the form of a fine powder, known asjloioers of sulphur, and 
composed of minute crystals. At a later stage, when the temperature 
of the condensing-chamber reaches 114°, the sulphur collects at the bot- 
tom as a liquid ; this is drawn off from time to time, and cast into elon- 
gated, conical moulds, forming roll sulphur. Its physical properties are 
affected by various conditions. Generally, sulphur appears as a light yel- 
low solid, having neither taste nor odor. At low temperatures (below 
— 50°), and when in a state of fine subdivision, it is almost colorless. 

It is dimorphous; crystallizes in oblique rhombic prisms when fused 
sulphur is allowed to solidify, and in rhombic octohedra when its solution 



COMPOUNDS OF HYDROGEN AND SULPHUR. 83 

in carbon disulphide is allowed to evaporate spontaneously. The two 
forms differ from each other in specific gravity : that of the prismatic 
sulphur being 1.95, and that of the octohedral 2.05. The fusing-point 
of the first variety is 120°; that of the second 114.5°. The prismatic 
variety does not remain such indefinitely ; transparent at first, it gradu- 
ally becomes opaque from a conversion of the prisms into collections of 
octohedra. 

When sulphur is heated it melts to a thin, yellow liquid at about 114°; 
at from 150° to 160° this becomes thick and brown ; toward 330° to 340° 
it becomes thinner and lighter in color again, and, finally, it boils at a 
temperature variously stated from 440° (Deville) to 448° (Becquerel), 
giving off a brownish yellow vapor. When heated to about 400° and 
suddenly cooled, it is converted into still another variety, known as 
plastic sulphur, which, for a time, is reddish brown, transparent, elastic, 
and so soft that it may be moulded into any desired form. At 1,000° 
the density of vapor of sulphur is 2.22A or 31. 75H. The best solvents 
of sulphur are protochloride of sulphur and carbon disulphide, a solution 
in the former containing 66.7 per cent, of sulphur at ordinary tempera- 
tures, and the latter dissolving 37.2 parts per 100 at 15°. It is also 
soluble to a less extent in aniline, phenol, benzol, benzine, and chloroform. 

Sulphur may be obtained as a white, very finely divided powder, by 
the decomposition of calcium sulphide. As thus prepared, it is the /Sul- 
phur prcecipitatum (U. S., Br.), or milk of sulphur. 

Sulphur unites readily with other elements, forming compounds 
which, except those formed with elements of the chlorine group and 
oxygen, are known as sulphides. When heated in contact with air or 
oxygen, it burns with a blue flame, giving off sulphur dioxide, S0 2 . In 
an atmosphere of hydrogen it burns with formation of hydrogen sulphide. 

The compounds of sulphur resemble in composition, and to some ex- 
tent in their chemical properties, the corresponding oxygen compounds 
when these exist. Thus, carbon disulphide, CS 2 , is an anhydride corre- 
sponding to carbon dioxide, C0 2 . In many organic substances sulphur 
may be made to replace oxygen ; thus, we have sulphocyanic acid, CNSH, 
corresponding to cyanic acid, CNOH. Sulphur is used in the arts, prin- 
cipally for the manufacture of gunpowder; also to some extent in making 
sulphuric acid, sulphur dioxide, and matches, and for the prevention of 
parasitic growths. It is not used medicinally to the same extent as 
formerly. We have only theoretical explanations of the method in 
which it is rendered capable of absorption. That it is absorbed when 
taken internally is, however, certain, from the fact that persons taking it 
excrete by the skin sufficient quantities of some compound of sulphur to 
blacken silver coins carried in their clothing:. 

Compounds of Hydrogen and Sulphur. 

Two of these are known — similar in composition to the oxygen com- 
pounds: 

Hydrogen sulphide H 2 S. 

Hydrogen persulphide H 2 S 2 . 

It is probable that there also exist other compounds containing a still 
higher proportion of sulphur. 



84 GENERAL MEDICAL CHEMISTRY. 



Hydrogen Sulphide. 

Sulphydric acid-^-Hydrosulphuric acid — Sulphuretted hydrogen — 
H 2 S — exists in nature in the volcanic gases; as a result of the decompo- 
sition of organic matters containing sulphur; and in solution in the wa- 
ters of some mineral springs. 

It may be obtained by the direct union of the elements, either by 
burning sulphur in hydrogen, or by passing a current of hydrogen 
through molten sulphur. At high temperatures vapor of sulphur decom- 
poses water with formation of hydrogen sulphide and pentathionic acid. 
It is also formed by the action of nascent hydrogen upon sulphuric acid, in 
the presence of zinc, if the mixture become heated. This last method of 
formation is of interest in connection with Marsh's test for arsenic (q. v.). 

When desired in the laboratory, it is obtained by one of the three fol- 
lowing reactions: 

First. — By the action of hydrochloric acid upon antimony trisulphide: 

Sb 2 S 3 + 6HC1 = 2SbCl 3 + 3H 2 S. 

Second. — The process usually adopted is by the action of diluted sul- 
phuric acid upon ferrous sulphide: 

FeS + S0 4 H 2 = S0 4 Fe + H 2 S. 

Tliird. — When the gas is required for toxicological analysis, it is es- 
sential that it should contain no hydrogen arsenide (which has been 
shown by Myers to be capable of existence in the presence of hydrogen 
sulphide); and as it is difficult to obtain ferrous sulphide free from 
arsenic, which would be converted into hydrogen arsenide under the con- 
ditions required for the formation of hydrogen sulphide, Otto has 
recommended that hydrogen sulphide be obtained in such cases by the 
action of hydrochloric acid upon calcium sulphide (q. v.): 

CaS + 2HC1 = CaCl 2 + H 2 S. 

By whatever method hydrogen sulphide is prepared, it must be washed 
before use by bubbling through water. 

Hydrogen sulphide is a colorless gas, having the odor of rotten eggs, 
and a correspondingly disgusting taste; sp. gr. 1.19 A — 17.2 H. Water 
at 15° dissolves 3.23 times its volume of the gas, which is also soluble in 
alcohol. At — 74°, at the ordinary pressure, or under a pressure of 17 
atmospheres, it liquefies; and solidfies at —85.5°, into white crystals. The 
density of the liquid is 0.9. 

Hydrogen sulphide burns in air with formation of sulphur dioxide and 
water: 

2H 2 S + 30 2 =2S0 2 + 2H 2 0. 

If the supply of oxygen be deficient, water is formed and elementary 
sulphur deposited: 

H 2 S + 0=H 2 + S. 

Mixtures of hydrogen sulphide and oxygen, or air, explode on the ap- 
proach of a flame. When hydrogen sulphide in solution is exposed to 



ACTION ON THE ECONOMY. 85 

the air, it is decomposed into separation of sulphur. Solutions should be 
made with boiled water and kept in bottles, which are completely filled 
and well corked. Oxidizing agents decompose hydrogen sulphide readily 
with separation of sulphur; it is also similarly decomposed by chlorine, 
bromine and iodine, which unite with its hydrogen. Sulphur dioxide and 
hydrogen sulphide mutually decompose each other (see p. 87). 

When the gas is passed through a solution of an alkaline hydrate, the 
oxygen of the hydrate is displaced by sulphur, with formation of a sulphy- 

H 2 S + KHO=H 2 + KHS. 

When directed through a solution of a metallic salt, hydrogen sul- 
phide relinquishes its sulphur to the metal — 

S0 4 Cu + H 2 S=CuS + S0 4 H 2 

— a property which renders it of great value in analytical chemistry. 

The presence of hydrogen sulphide, even in minute quantities, may 
be detected by its odor, and by the brown or black coloration which it 
produces in a piece of filter-paper moistened with solution of lead acetate. 



Action on the Economy. 

Hydrogen sulphide exists in small quantity in the gases of the intes- 
tine, where it results from the decomposition of albuminous material, or 
from that of taurocholic acid; it also occurs occasionally in abscesses and 
in the urine in tuberculosis, variola, and cancer of the bladder, resulting 
from the decomposition of some unknown sulphurized body. In certain 
exceptional cases the gas may also reach the bladder by diffusion from 
the rectum (Betz). 

When inhaled, hydrogen sulphide is an active poison. An animal 
placed in an atmosphere of the gas dies almost immediately, and the 
moderately diluted gas is still rapidly fatal. The minimum proportion in 
which it is fatal to human life is stated by Letheby to be one per cent., 
although Gaultier de Claubry claims that workmen have existed for some 
time in an atmosphere containing three per cent. Even when highly 
diluted, it produces, when inhaled, a low, febrile condition; and care 
should be had that the air of laboratories in which it is used is not con- 
taminated by it. 

The researches of Kaufmann and Rosenthal, Diakonaw and Preyer, 
leave no doubt that the toxic effects of hydrogen sulphide are due prima- 
rily, if not entirely, to its reducing and combining with the coloring- 
matter of the red blood-corpuscles. 

Sewer-gases. — It is but rarely that a human being inhales simple mix- 
tures of air with hydrogen sulphide. The latter generally produces its 
deleterious effects as a constituent of the gases emanating from sewers, 
privies, burial-vaults, etc., in which it exists both in its own form and as 
ammonium sulphydrate. Cases of accidental (if the adjective be admis- 
sible) poisoning from sewer-gases are of two forms: 1. Slow poisoning, 
sometimes terminating fatally, by sewer-gases diluted with air and trace- 
able to defective plumbing; generally in dwellings " fitted with all the 
modern conveniences." Very common, although easily preventable by 



86 GENERAL MEDICAL CHEMISTRY. 

proper trapping and ventilation of soil- and waste-pipes. 2. Cases which 
may be designated as acute, in which the gas is inhaled in a more concen- 
trated form, as by those entering sewers or engaged in the removal of 
night-soil. The victim usually falls as if by the effect of a sudden blow,. 
and, even if rescued within a few moments, frequently dies within twenty- 
four hours. 

The treatment should consist in promoting the inhalation of fresh air — 
by artificial respiration if necessary, cold affusions, the administration 
of hot brandy and water, and the inhalation of air containing a trace of 
chlorine. 

In cases of death the blood is very dark in color, and on spectroscopic 
examination shows the bands of sulphaemoglobin. 



Sulphur Dioxide. 

Sulphurous anhydride — Sulphurous acid — Sulphurous oxide — S0 2 . — 
Sulphur dioxide exists in volcanic gases, and in solution in some natural 
waters. 

It is prepared by burning sulphur in air. This method is adopted 
when the gas is required as a disinfectant, and in some sulphuric acid 
factories. 

By roasting iron pyrites in a current of air, in most sulphuric acid 
factories. 

During the combustion of coal or coke containing sulphur, and of 
coal-gas contaminated with carbon disulphide. 

By heating strong sulphuric acid with copper turnings: 

2S0 4 H 2 + Cu = S0 4 Cu + 2H 2 + S0 2 . 

The acid is brought in contact with the metal and heated until the 
action begins, after which the heat is moderated, or, if the action become 
too violent, withdrawn entirely. This is %he method followed for obtain- 
ing the gas in the laboratory. The product must be passed through a 
small quantity of water. The same reduction of sulphuric acid is accom- 
plished by other substances, such as sulphur, carbon, mercury, and silver. 
According to the United States and British Pharmacopoeias, charcoal is 
to be used. 

Sulphur dioxide is a colorless gas, having a suffocating odor (that of 
burning sulphur matches), and a disagreeable and persistent taste. Sp. 
gr. 2.234 A — 32.25 H. It may be easily liquefied at — 10°, forming a 
colorless, mobile, transparent liquid, which solidifies at — 75° and boils at 
— 8°. By a rapid evaporation of the liquid, a temperature of — 65° is 
obtained. It is very soluble in water, which, at 15°, dissolves more than 
forty times its volume. It is also very soluble in alcohol. 

Sulphur dioxide is not a supporter of combustion, nor will it burn in 
air. When heated in contact with hydrogen, it is decomposed with 
formation of water and separation of sulphur. In presence of nascent 
hydrogen, however, hydrogen sulphide and water are formed. 

Water not only dissolves the gas, but forms with it a true hydrate, 
S0 3 H 2 , which exists in the solution. A hydrate of this acid, crystalline, 
fusible at +4°, and having the composition S0 3 H 2 -h8H 2 0, has been sepa- 
rated. While, therefor, the name sulphurous acid is incorrect as applied 
to the gas, it is perfectly applicable to the solution. Such a solution is 



SULPHUR TRIOXIDE. 87 

officinal under the name Acidum sidphurosum (U. S., Br.) (U. S. sp. gr., 
1.035 — Br. sp. gr. 1.04; both nearly saturated at the ordinary tempera- 
ture). 

It is a valuable reducing agent, for which purpose it is frequently 
used, either in the gaseous form or in solution. Its deoxidizing power is 
due to the absorption of oxygen by the sulphurous acid to form sulphuric 
acid: 

S0 3 H 2 + = S0 4 H 2 ; 
SO a +H a O+0=S0 4 H 2 . 

It decolorizes vegetable substances, without, however, permanently 
destroying the pigment; for if an organic substance, bleached by sulphur 
dioxide, be washed with dilute sulphuric acid, the color is restored. Its 
bleaching power is utilized in the manufacture of straw, silk, and woollen 
goods. It is probable that this decoloration is due to an oxidation of 
sulphurous acid at the expense of the oxygen of water, the nascent hy- 
drogen uniting with the coloring-matter to form a colorless compound, 
as indigotine is converted into white indigo by the action of reducing 
agents. It is also used as a disinfecting and deodorizing agent — probably 
behaving toward other organic matters as toward the pigments. Its chief 
value, however, for this purpose is in the destruction of hydrogen sul- 
phide, which it brings about with formation of water and pentathionic 
acid, and liberation of sulphur: 

4S0 2 + 3H 2 S = 2H 2 + S 5 6 H 2 + S 2 . 

In this case it is not a reducing, but an oxidizing agent. 

Sulphur dioxide and chlorine combine directly under the influence of 
sunlight to form a liquid having the composition S0 2 C1 Q , the chloride of 
the divalent radical sulphuryl (S0 2 )", which also exists in sulphuric acid, 
and which may be considered as existing free in sulphur dioxide, as 
carbonyl (CO)'' exists free as carbonic oxide. 

Corresponding to sulphurous acid, which is dibasic, are salts known as 
sulphites. 

Although poisonous when inhaled in the concentrated form, it can only 
be regarded as annoying when largely diluted with air; moreover, in- 
dividuals become quickly habituated to inhaling air containing compara- 
tively large quantities of this gas. A delicate reagent for the presence 
of sulphur dioxide is obtained by moistening paper, impregnated with 
starch paste, with a solution of iodic acid; a mere trace of the gas, 1 to 
3,000, in air, is sufficient to reduce the iodic acid, when the liberated iodine 
produces a blue color with the starch. 



Sulphur Trioxide. 

Sulphuric anhydride — Sulphuric oxide, S0 3 . — Although formed by 
the direct union of sulphur dioxide and oxygen, at 250°-300°, and in the 
presence of spongy platinum, this substance is more easily obtained from 
Nordhausen sulphuric acid (q. v.), by distillation at a temperature below 
100°, and collection of the vapors in a condenser cooled by a mixture of 
ice and salt. 

It appears in the form of white, silky needles. It is capable of exist- 



88 



GENERAL MEDICAL CHEMISTRY. 



ing in two forms, which differ from each other in their fusing and boiling 
points. It has a great tendency to unite with water to form sulphuric 
acid — 

:SOJEL 



S0 3 + H 2 0: 



L 2> 



and when exposed to the air it gives off white fumes of that substance, 
formed by union with atmospheric moisture. When it is thrown into 
water a hissing sound is observed, and there is a marked elevation of tem- 
perature. When perfectly pure it does not redden dry, blue litmus 
paper ; nor has it any corrosive action upon animal tissues until, by 
absorption of moisture, it is converted into sulphuric acid. 

Berthelot has described another oxide of sulphur, having the composi- 
tion S 2 0_ — an unstable, crystalline body, formed by the union of sulphur 
dioxide and oxygen, under the influence of silent electric discharges. 

Oxacids of Sulphur. 

These compounds form an extended series, some of the terms of 
which are very important industrial products. They may be divided into 
two groups, some of the members of which are known only in combi- 
nation. 



S0 2 H 2 Hydrosulphurous acid. 
S0 3 H 2 Sulphurous acid. 
S0 4 H 2 Sulphuric acid. 

S 2 3 H 2 Hyposulphurous acid. 
S 2 7 H 2 Pyrosulphuric acid. 



S 2 6 H 2 Dithionic acid. 
S 3 6 H 2 Trithionic acid. 
S.O.H„ Tetrathionic acid. 

4 6 2 

S 5 6 H 2 Pentathionic acid. 



It is unfortunate that the name hyposulphurous acid (hyposulphites), 
should have been applied and retained by usage, to the compound 
S 2 3 H 2 , as it properly belongs to S0 2 H 2 ; discovered by Schutzenberger 
in 1869. The so-called hyposulphurous acid may be considered as formed 
by the union of two molecules of S0 2 H 2 , with separation of a molecule of 
water; or as sulphuric acid in which one atom of oxygen has been re- 
placed by an atom of sulphur. 

Hydrosulphurous Acid — S0 2 H 2 . 

Is only known in solution, in which form it is obtained by the action 
of zinc upon sulphurous acid in solution. It is an unstable body, and a 
powerful bleaching and deoxidizing agent. Upon its deoxidizing power 
Schutzenberger and Risler have based a process for the quantitative 
determination of oxygen, admirably adapted for use in analysis of blood.* 

Sulphuric Acid— S0 4 H 2 . 

This acid, or rather the commercial product containing it, is manufac- 
tured in enormous quantities, and may be said to be the basis of chemical 
industry, as there are but few processes of chemical technology into 
some part of which it does not enter. 



* Bull. Soc. Chiin. Paris, xix., 152 ; xx., 145. 



SULPHURIC ACID. 89 

It was known to the earlier alchemists as spirits of Roman vitriol; 
they obtained it by the distillation of ferrous sulphate, a method still fol- 
lowed for the manufacture of the so-called Nordhausen acid (q. v.). 

The method by which the commercial acid is now obtained is the re- 
sult of gradual improvement, through a period of time beginning in the 
early part of the seventeenth century. In its present form it may be divided 
into two parts: 1st, the formation of a dilute acid; and 2d, the concen- 
tration of this product. 

The first part is carried on in immense chambers of timber, lined with 
lead, and furnishes an acid having a specific gravity of 1.55, and containing 
sixty-five per cent, of true sulphuric acid, S0 4 H 2 . Into these leaden cham- 
bers sulphur dioxide, obtained by burning sulphur or by roasting pyrites, 
is driven along with a large excess of air. In the chambers it comes in 
contact with nitric acid, at the expense of which it is oxidized to sul- 
phuric acid, while nitrogen tetroxide (red fumes) is formed: 



S0 2 + 2N0 3 H=S0 4 H 2 + 2N0 2 . 

• 



Were this the only reaction, not only would the cost of sulphuric acid 
be much greater than it is, but the disposal of the red fumes would offer 
serious obstacles to its manufacture. To avoid these difficulties, a second 
reaction is resorted to. Water in the form of steam, or of fine spray, is 
discharged into the chambers, and, coming in contact with the nitrogen 
tetroxide, converts part into nitric acid and part into nitrogen dioxide: 

3NO a + H a O=2NO,H + NO. 

The nitrogen dioxide, in contact with the oxygen of air carried into 
the chamber, forms nitrogen tetroxide — 

NO + 0=N0 2 , 

which in turn yields more nitric acid. These series of changes go on con- 
tinuously, the supply of sulphur dioxide and water being carefully regu- 
lated to the required proportions, and the nitric acid acting merely as a 
carrier of oxygen from the air to the acid. 

The acid is allowed to collect in the chambers until it has the sp. gr. 
1.55, when it is drawn off. This chamber acid, although used in a few 
industrial processes, is not yet strong enough for most purposes. It is 
■concentrated, first by evaporation in shallow leaden pans until its specific 
gravity reaches 1.746; at this point it begins to act upon the lead, and 
is transferred to platinum stills, where the concentration is completed. 

The product is of three grades, according to the extent to which the 
concentration has been carried: sp. gr. 1.833 = 93 per cent., S0 4 H 2 ; sp. gr. 
1.840 = 98 per cent., S0 4 H 2 ; and sp. gr. 1.840=99£ per cent., S0 4 H 2 . 

The commercial acid is an oily liquid, having a more or less pro- 
nounced brown tinge, and is known as oil of vitriol. It still contains 
many impurities, from which it is partially freed by distillation in glass, 
the product being the so-called C P., or chemically pure acid, which is, 
however, rarely so. 

The pure acid is a colorless, oily liquid; sp. gr. 1.842 at 12°; solidifies 
at 10.5°, and boils at 338°, although ebullition seems to begin at 290°. It 
is odorless, intensely acid in reaction and in taste, and highly corrosive. 



90 



GENERAL MEDICAL CHEMISTRY. 



The specific gravity varies with the amount of water, as shown in the 
following table: 



DENSITIES OF SOLUTIONS OF SULPHURIC ACID AT +15°, 

AFTER J. KOLB. 



11 


Specific 
gravity. 


o 

a, 


02 8, 


C sin 

bog 


as 

CO bD 


o 

CTO 

p. 


O n 

00 S. 


Degree 
Baum6. 


Specific 
gravity. 


i . 

o 


9 S 

CC c. 





1.000 


0.7 


0.9 


23 


1.190 


21.1 


25.8 


46 


1.468 


46.4 


56.9 


1 


1.007 


1.5 


1.9 


24 


1.200 


22.1 


27.1 


47 


1.483 


47.6 


58.3 


2 


1.014 


2.3 


2.8 


25 


1.210 


23.2 


28.4 


48 


1.498 


48.7 


59.6 


3 


1.0.22 


3.1 


3.8 


i 26 


1.220 


24.2 


29.6 


49 


1.514 


49.8 


61.0 


4 


1.029 


3.9 


4.8 


27 


1.230 


25.3 


31.0 


50 


1.530 


51.0 


62.5 


5 


1.037 


4.7 


5.8 


28 


1.241 
1.252 


26.3 


32.2 | 


51 


1.540 


52.2 


64.0- 


6 


1.045 


5.6 


6.8 


29 


27.3 


33.4 


52 


1.563 


53.5 


65.5 


7 


1.052 


6.4 


7.8 


30 


1.263 


28.3 


34.7 


53 


1.580 


54.9 


67.0 


8 


1.060 


7.2 


8.8 


31 


1.274 


29.4 


30.0 


54 


1.597 


56.0 


68.6- 


9 


1.067 


8.0 


9.8 


32 


1.285 


30.5 


37.4 


55 


1.615 


57.1 


70.O 


10 


1.075 


8.8 


10.8 


33 


1.297 


31.7 


38.8 


56 


1.634 


58.4 


71.6 


11 


1.083 


9.7 


11.9 


34 


1.308 


32.8 


40.2 


57 


1.652 


59.7 


73.2 


12 


1.091 


10.6 


13.0 


35 


1.320 


33.9 


41.6 i 


58 


1.671 


61.0 


74.7 


13 


1.100 


11.5 


14.1 


36 


1.332 


35.1 


43.0 


50 


1.691 


62.4 


76.4 


14 


1.108 


12.4 


15.2 


37 


1.345 


36.2 


44.4 


60 


1.711 


63.7 


78.1 


15 


1.116 


13.2 


16.2 


38 


1.357 


37.2 


45.5 


61 


1.732 


65.2 


79.9 


16 


1.125 


14.1 


17.3 


39 


1.370 


38.3 


46.9 


62 


1.753 


66.7 


81.7 


17 


1.134 


15.1 


18.5 


40 


1.383 


39.5 


48.3 ; 


63 


1.774 


68.7 


84.1 


18 


1.142 


16.0 


19.6 


41 


1.397 


40.7 


49.8 | 


64 


1.796 


70.6 


86.5 


19 


1.152 


17.0 


20.8 


42 j 


1.410 


41.8 


51.2 , 


65 


1.819 


73.2 


89.7 


20 


1.162 


18.0 


22.2 


43 


1.424 


42.9 


52.8 


66 


1.842 


81.6 


100.0 


21 


1.171 


19.0 


23.3 


44 ! 


1.433 


44 1 


54.0 


| 


j 






22 


1.180 


20.0 


24.5 1 


45 


1.453 


45.2 

j 


55.4 ; 











When the vapor of sulphuric acid is heated to redness, it is decom- 
posed into oxygen, water, and sulphur dioxide. It is also reduced, with for- 
mation of sulphur dioxide, by many substances, such as sulphur, phos- 
phorus, carbon, mercury, copper, and silver. 

Sulphur trioxide unites with water to form at least three definite 
hydrates: one, the compound S 2 7 H 2 , which will be considered below; 
another, the so-called monohydrated acid, S0 4 H 2 , or, true sulphuric acid; 
and a third, sometimes called the bihydrated acid, having the composition 
S0 4 H 2 + H 2 0, which crystallizes in large prisms, fusible at +8.5°; sp. gr. 
1.788. 

When sulphuric acid is mixed with water, there is an elevation of 
temperature which amounts to 100° when four volumes of acid are mixed 
with one volume of water. The tendency of sulphuric acid to absorb water is 
such that it is frequently used as a drying agent, absorbing water from the 
surrounding air or from gases which are caused to bubble through it. 
For the same reason it is unsafe to leave the acid' in a vessel exposed to 
the air, as it is liable to absorb moisture to such an extent that by in- 
crease of bulk it overflows. When mixtures of acid and water are to be 
made, the acid should be added to the water (in a vessel of thin glass). 

Owing to its affinity for water, sulphuric acid destroys many organic 



ACTION ON THE ECONOMY. 91 

substances, removing from them the elements of water, and, in the case 
of the carbohydrates, leaving a residue of carbon. 

Sulphuric acid is a powerful dibasic acid. 

The presence of sulphuric acid or of a soluble sulphate may be de- 
tected by the formation of a white precipitate of barium sulphate with 
chloride or nitrate of barium in an acid solution. This precipitate, when 
dried, mixed with charcoal and strongly heated, is converted into barium 
sulphide; which, when moistened with hydrochloric acid, gives off hydro- 
gen sulphide, recognizable by the blackening of paper moistened with 
solution of lead acetate. 

There are three varieties of sulphuric acid used in pharmacy. The 
Acidum sidphuricum (U. S., Br.), the so-called C. P. acid, having a 
specific gravity of 1.842, used only in the preparation of other pharma- 
ceutical preparations; Acidum sidphuricum dilution (U. S., Br.), the last 
mentioned diluted with water to sp. gr. 1.082 U. S., containing 11.9$ 
S0 4 H 2 (sp. gr. 1.094, Br., containing about 13$ S0 4 H 2 ); Ac. sidph. aro- 
maticum (U. S., Br.), containing about the same proportion of acid as 
the Ac. sulph. dil., U. S. 

Impurities. — The commercial acid is so charged with foreign sub- 
stances as to render it entirely unfit for medicinal and for any but the 
coarsest chemical uses. Even the C. P. acid is obtained sufficiently free 
from certain impurities for toxicological analysis only with considerable 
difficulty. The principal impurities are the following: lead, recognizable 
by the production of cloudiness when the acid is diluted with water, 
lead sulphate being less soluble in dilute than in concentrated acid. 
Potassium sulphate, fraudulently added to increase the specific gravity, 
"may be detected by evaporating to dryness. Organic matter, communi- 
cating a dark color to the acid. These impurities do not occur in the 
C. P. acid. An acid to be used in toxicological analysis should respond 
favorably to the following tests: it should be perfectly colorless, even 
after dilution with four volumes of water and treatment with hvdrogren sul- 
phide. The residue of its evaporation should be insignificant in quantity; 
and when moistened with a few drops of water, it should give no color 
with solution of potassium ferrocyanide. At least two fluid ounces, 
diluted with water, should give no arsenical stain in a Marsh apparatus, 
with pure zinc, during a heating of two hours (see p. 129). For cer- 
tain purposes it is necessary to have an acid free from the oxides of 
nitrogen; such an acid cannot be bought, and can only be obtained by 
careful distillation of the purest purchasable acid, to which ammonium 
sulphate has been added, and the collection separately of those parts of 
the distillate which give no color with a solution of brucia. 



Action on the Economy. 

Although it is possible that sulphuric acid, taken in the diluted form 
in sufficient quantity, and during a sufficiently extended period of time, 
may act as a true poison in diminishing or destroying the alkaline reaction 
of the circulating fluids, we have no record of serious consequences 
resulting from its poisonous action. When, however, it comes in con- 
tact with any tissue, whether external or internal, in the concentrated or 
even moderately diluted form, it is one of the most active of corrosives; 
and cases are of frequent occurrence in which " death or serious bodily 
harm" have resulted from its being taken by suicides, or taken or admin- 



92 GENERAL MEDICAL CHEMISTRY. 

istered by mistake. It is rarely administered with murderous intent, 
-although it is very frequently thrown upon the body, with design to 
destroy the clothing or disfigure the person. The action of the acid is 
to destroy (to disorganize) any organic substance with which it may 
come in contact, and is therefor immediate. The majority of cases ter- 
minate fatally, either within a few hours, from corrosion and perforation 
of the oesophagus and stomach; or, exceptionally, from passage of the 
acid into the air-passages, and consequent asphyxia ; or, weeks or 
months after the ingestion of the acid, from starvation, due to destruc- 
tion of the mucous surfaces of the alimentary canal, or closure of the 
pyloric orifice of the stomach (secondary effects, improperly called 
ci chronic poisoning"). 

The treatment consists in neutralizing the acid as quickly as possible, 
by the administration of slacked lime, or preferably, of magnesia, and in 
supplying materials for nutrition per rectum. The administration of 
such substances as white of egg, oil, etc., is mere waste of time. The 
use of the stomach-pump, when sulphuric acid or any corrosive has been 
taken, is liable to make matters worse by perforating the weakened walls 
of the oesophagus or stomach. 

The detection of sulphuric acid in the body after death is rarely called 
for ; when it is, it can only be accomplished by a quantitative analysis. 

Within a few years the practice of " vitriol-throwing" has become quite 
]3revalent, and the physician may be called upon to state whether stains 
upon the clothing or person are or are not produced by this acid. Fabrics 
moistened by the acid are corroded and fall to pieces readily. If dyed of a 
dark color, a stain is produced which is brick-red when fresh and brown- 
ish when old ; if not too old, it is removed when moistened with ammo-" 
nium hydrate, which also removes stains of hydrochloric acid (distinguish- 
able by being of a brighter red), but not those of nitric acid, which are 
brownish yellow in color. 



Hyposulphurous Acid — S 2 3 H 2 , 

Has not been isolated; the corresponding salts, hyposulphites, are used 
in medicine and in the arts. 



Pyrosulphuric Acid. 

Faming sulphuric acid — Nordhausen sulphuric acid — Disulphuric 
hydrate — S 2 7 H 2 — contained in the product known as Nordhausen oil of 
vitriol, obtained by distillation of ferrous sulphate. If the first portions 
of this distillate be separated, they become solid at the ordinary tem- 
perature, and by repeated fusions, crystallizations, and draining of the 
crystals, a substance is finally obtained having the above composition, 
and fusing at 35°. It forms salts called pyrosulphates or disulphates. 

The commercial Nordhausen acid is a brown, oily liquid, fuming when 
exposed to the air, solidifying when cooled to 0°, and giving off S0 4 H 2 
and S0 3 when heated. It is used in the arts, in the manufacture of 
certain coloring matters (alizarin, eosin), and as a solvent for indigo 
(sulphindigotic acid). 

The series of thionic acids have as yet only a theoretical interest. 
Dithionic or hyposulphuric acid — S 2 6 H a — is obtained as an unstable, 



SELENIUM AND TELLURIUM. 93 

acid, syrupy liquid, sp. gr. 1.437, by passing sulphur dioxide through 
water holding manganese dioxide in suspension, decomposition with 
barium sulphide and sulphuric acid in proper proportion, and subsequent 
concentration in vacuo. 

Trithionic acid, S 3 6 H 2 — obtained in a very acid, bitter, odorless 
solution by passing sulphur dioxide through a solution of potassium hypo- 
sulphite, decomposing the solution of potassium trithionate, thus formed 
with tartaric, perchloric, or hydrofluosilicic acid, and concentrating the 
solution in a dry vacuum. 

Tetrathionic acid, S 4 6 H 2 — obtained in acid, colorless, odorless solu- 
tion, by decomposing a solution of its barium salt, prepared by the 
action of iodine upon barium hyposulphite. 

JPentathionic acid, S 5 6 H 2 — obtained in aqueous solution by the 
action of hydrogen sulphide upon solution of sulphurous acid. 



Compounds of Sulphur, with Chlorine, Bromine, and Iodine. 

There is but one chloride of sulphur, S 2 C1 , which is formed when dry 
chlorine is passed through an excess of sulphur heated to fusion; the pro- 
duct is purified by redistillation. An oily, yellow fluid, boiling at 136°, 
having a disagreeable, nauseous odor and fuming when exposed to the 
air. It dissolves sulphur abundantly, and such a solution, mixed with 
benzine or with carbon disulphide, is used in the vulcanization of rubber. 
Other chlorides of sulphur SC1 2 , and SC1 4 , have been described, but their- 
existence is problematic. 

A single bromide of sulphur, S 2 Br 2 , is known as a very unstable red 
liquid, boiling at 215°, and formed by the action of bromine upon sulphur 
dioxide in the presence of phosphorus trichloride. 

An iodide of sulphur, S 2 I a , is formed as a steel-gray, crystalline mass, 
fusible at 60°, when equivalent quantities of sulphur and iodine are 
gently heated to fusion together, Sulphuris iodidum (U. S., Br.), or by 
the action of sulphur chloride upon ethyl iodide. Other ill-defined iodides 
have been described. 



SELENIUM AND TELLURIUM. 

Se 79.5 

Te 128 

Selenium. — Discovered in 1817 by Berzelius; an element existing in 
very small quantities and in limited distribution in combination with sul- 
phur, and as the selenides of lead, mercury, silver, and copper. It is capa- 
ble of existing in two allotropic forms. In its compounds it closely re- 
sembles sulphur. Neither the element nor any of its compounds has been 
utilized in the arts or in medicine. 

Tellurium. — One of the least common of the elements; discovered in 
1782, by Milller, of Reichenstein. It exists in nature uncombined, and 
as the tellurides of bismuth, lead, silver, antimony, nickel, and gold. 

It is a solid body, having a metallic lustre, fusible at about 500°, and 
capable of distillation in an atmosphere of hydrogen. In its chemical 
properties and compounds it resembles sulphur and selenium. Its use in 
medicine has been attempted, but abandoned. 



94 



GENEKAL MEDICAL CHEMISTKY. 



III. NITROGEN GROUP. 

NlTROGEN N 14 

Phosphorus P 31 

Arsenic As 75 

Antimony Sb 122 

The elements of this group are either trivalent or pentavalent. With 
hydrogen they form non-acid compounds composed of one volume of the 
element in the gaseous state with three volumes of hydrogen, the union 
being attended with a condensation of volume of one-half. Their hydrates 
are acids containing one, two, three, or four atoms of replaceable hydrogen. 

Bismuth, frequently classed in this group, is excluded, owing to the 
existence of the nitrate (N0 3 ) 3 , Bi. The relations existing becween the 
compounds of the elements of this group are shown in the following table: 



NH 3) 


N a O, 


NO, N 2 3 , 


N0 3 , 


NA, 


Ammonia. 


Nitrogen 
monoxide. 


Nitrogen Nitrogen 
dioxide. trioxide. 


Nitrogen 
tetroxide. 


Nitrogen 
pentoxide. 


PH S , 




PA, 




PA, 


Hydrogen 
phosphide. 




Phosphorus 
trioxide. 


i 


Phosphorus 
pentoxide. 


AsH„ 




As 2 O s , 




As A, 


Hydrogen 
arsenide. 




Arsenic 
trioxide. 




Arsenic 
pentoxide. 


SbH 3 , 




Sb 2 3 , 




SbA, 


Hydrogen 
antimonide. 




Antimony 
trioxide. 




Antimony 
pentoxide. 

N0 3 H, 

Nitric 
acid. 


P0 3 H„, 


P0 3 H a , 


P0 4 H 3 , 


P,0,H„ 


P0 3 H, 


Hypophosphor- 
ons acid. 


Phosphorous 
acid. 


Phosphoric 
acid. 


Pyrophosphoric 
acid. 


Metaphosphoric 
acid. 




AsO s H 3 


As0 4 H 3 , 


As 2 7 H 4 , 


AsO : ,H, 




Arsenious 
acid. 


Arsenic 
acid. 


Pyroarsenic 
acid. 


Metarsenic 
acid. 






SbO,H 3 , 


Sb,0,H„ 


Sb0 3 H, 






Antimonic 
acid. 


Pyroantimonic 
acid. 


Metantimonic 
acid. 


' 




NITROGEN. 




■ 




N 




14 





First recognized as the irrespirable constituent of atmospheric air by 
Dr. Rutherford, of Edinburgh, in 1772, and by him called aer mephiticus ; 
subsequently " rediscovered " by Scheele and Lavoisier, in 1777, and named 



ATMOSPHERIC AIR. 95 

azote (d far]) by the latter, a name still retained by French chemists. The 
name nitrogen {yirpov yeVeo-is) was given subsequently by Chaptal. 

It exists in nature uncombined as one of the constituents of atmos- 
pheric air, and in combination in mineral substances, as well as in some of 
the most important of organic bodies. 

It is usually obtained from atmospheric air by removal of oxygen, as 
by burning phosphorus in a limited quantity of air, or by passing a slow 
current of air over' copper heated to redness. As thus obtained, nitrogen 
is contaminated with other constituents of air, carbon dioxide, etc.; to 
obtain it in a state of purity, recourse is had to decomposition of ammo- 
nium hydrate by chlorine gas, care being had, however, that the ammoni- 
acal compound is always present in excess, to avoid the formation of the 
highly explosive nitrogen chloride. 

It is a tasteless, odorless, colorless gas, non-combustible, and not a sup- 
porter of combustion ; sp. gr. 0.972A — 14.041H; very sparingly solu- 
ble in water and in alcohol. 

Nitrogen is very slow to enter into combination with other elements, 
and its compounds, once formed, are, as a rule, very prone to decomposi- 
tion, either sudden with explosion, or gradual by putrefaction. Nitro- 
gen and oxygen are capable of uniting directly under the influence of 
electric discharges. Direct union of nitrogen and hydrogen does not 
take place under ordinary conditions, but does under the influence of 
electric discharges, and during the decomposition of organic substances 
containing nitrogen. Nitrogen exerts no poisonous action when inhaled ; 
an animal in an atmosphere of pure nitrogen dies from simple lack of 
oxygen. This gas has been put to no use in the arts, and is used in the 
laboratory only when an atmosphere possessing the negative qualities of 
nitrogen is desired. 

Atmospheric Air. 

By the alchemists, and until the latter half of the seventeenth cen- 
tury, air was supposed to be an elementary substance, its compound nature 
being first recognized by Mayow in his Tractatus quinque medico-physici, 
published in 1669. It was not, however, until 1770 that Priestley re- 
peated and amplified the researches interrupted by the death of Mayow, 
nearly a century before. Subsequently the labors of Scheele, Lavoisier, 
and Rutherford added largely to the value of Priestley's and of Mayow's 
discoveries. 

The composition of atmospheric air, under varying conditions of time, 
location, temperature, pressure, etc., has been the subject of many and 
elaborate investigations, which have shown that, notwithstanding the 
fact that air is a mere mechanical mixture, and notwithstanding the ad- 
ditions to and subtractions from its constituent gases, to which it is sub- 
jected by the processes of animal and vegetable life, its composition is 
nearly constant; slight variations only having been observed in the quan- 
tity of gases present in small amounts. Leaving these out of considera- 
tion, air is composed of : 

By volume. By weight. 

Oxygen 20.93 23 

Nitrogen 79.07 77 

The mean of two hundred and thirty-three analyses by Regnault, of 
air from different locations, gives as the proportion of oxygen in volume: 



96 GENERAL MEDICAL CHEMISTKY. 

20.953; the extremes being 20.908 and 20.999. When air is dissolved in 
water the proportion of its constituent gases does not remain the same, 
as would be the case were it a definite compound ; but each gas is dis- 
solved according to its own solubility in water. As oxygen is more solu- 
ble than nitrogen, dissolved air is richer in the former gas than is that 
existing free. According to Bunsen, water saturated with air at 13° 
contains : 

Oxygen 34.73 

Nitrogen 65.27 

Besides these two main constituents, air contains about four to five 
thousandths of its bulk of other substances: vapor of water, carbon dioxide, 
ammoniacal compounds, hydrocarbons, ozone, oxides of nitrogen, and 
solid particles held in suspension. 

Vapor of water. — The proportion of vapor of water in the atmos- 
phere varies greatly at different times, and at varying distances from 
large bodies of water, the air being rarely completely saturated with 
water and never entirely free therefrom. Atmospheric moisture is either 
visible, as in fogs, clouds, etc.; or invisible, in solution, as it were. The 
quantity of water which air is capable of thus holding in solution is 
greater at high than at low temperatures and pressures. Any sudden di- 
minution of temperature or pressure of an air holding a large quantity 
of moisture will bring about the condensation of the moisture into drop- 
lets. Dew and hoar-frost are thus produced by diminution of tempera- 
ture during the night. Clouds are formed by the air rising from the sur- 
face, becoming colder in the upper atmospheric layers, and being there 
under less barometric pressure than at the surface, where it has become 
charged with moisture. Frequently also a current of cold air, mixing 
with air that is warmer and charged with moisture, determines the forma- 
tion of clouds or fogs, the latter being simply clouds near the surface. 

The actual amount of water in air is determined by passing a known 
volume of air through tubes filled with some drying agent, such as cal- 
cium chloride, whose increase of weight represents the weight of water 
contained in the volume of air acted upon. The amount of water in the 
atmosphere varies from three to sixteeta. volumes of vapor per thousand 
of air; being, as a rule, less in winter than in summer; less in northern 
latitudes than in the tropics; less in inland regions than in the vicinity 
of large bodies of water; less at high altitudes than at the sea-level; and 
less in cleared than in wooded districts. Near the sea-shore the air con- 
tains more moisture when the wind blows from the sea than when it 
blows in the opposite direction. 

The degree of dampness of the air does not depend upon the abso- 
lute quantity of watery vapor which it contains, but upon the propor- 
tion existing between that quantity and the amount of water which the 
air could hold if saturated with moisture at the same temperature and 
pressure; a proportion which is known as the fraction of saturation of 
the air; or its hygrometric condition, determined by instruments called 
hygrometers, hygroscopes, or psychrometers. While the air in winter is 
usually more damp than in summer, it contains an absolute quantity of 
water, less in the winter than in the summer; but, being in the former 
season more nearly saturated, its tendency to precipitate the moisture is 
greater; while during the summer months, on the other hand, the air, 
although containing more aqueous vapor than in winter, is, at the reigning 



ATMOSPHERIC AIR. 97 

temperature, less nearly saturated, and consequently more capable of ex- 
erting a drying influence by taking up a further quantity of water. 

The degree of saturation influences the body temperature materially 
by impeding or promoting evaporation from the surface, which is 
greater the less near the air is to its point of saturation. Heat is, there- 
for, more oppressive when the air is moist than when it is dry. Life may 
be, for the same reason, maintained at a much higher temperature if the 
air be dry than if it be moist. 

When dwellings are heated artificially in winter, the air should be 
charged with vapor of water by placing a pan containing water on the 
stove or in the air-box of the furnace; for, although the actual amount of 
moisture is not diminished, the degree of saturation is, and the air in 
consequence becomes dry and close unless vapor of water be added. 

Carbon dioxide. — The quantity of atmospheric carbon dioxide varies 
from three to six parts in ten thousand by volume, the average in the 
country being four in ten thousand. The amount is greater in cities, or 
in the neighborhood of natural or artificial sources of the gas, than in the 
open country; on land greater during the night than during the day. 
At sea the reverse is the case, the difference being due to the removal 
of carbon dioxide by plants under the influence of sunlight in the one 
case, and to the greater solubility of the gas in cold than in warm water in 
the second. The quantity is also greater in the atmospheric layers 
nearest the earth than in those at greater elevations (see p. 237). 

Other substances contained in air — Ammoniacal compounds. — Air 
contains small quantities of ammoniacal salts, carbonate, nitrate, and 
nitrite, the products of the decomposition of animal and vegetable sub- 
stances. They are present in very small amount, not exceeding a few 
millionths, and are taken up by plants, by which they are assimilated. 
Frequently in cold, dry weather, ammonium nitrate will be found con- 
densed as a snow-white crust on the sides of ventilators from stables,. 
urinals, etc. 

Hydrocarbons. — In the air of cities undetermined hydrocarbons have 
been detected to the maximum extent of 0.0001 part by volume. In the 
air of swampy places the proportion is greater (see Marsh-gas). 

Nitric and nitrous acids exist in combination, usually with ammonia. 
They are produced either by the oxidation of combustible substances, or 
by direct union of nitrogen with vapor of water under the influence of 
electric discharges. Rain-water falling during thunder-showers contains 
comparatively large quantities of ammonium nitrate. 

Solid particles in suspension in air are exceedingly diverse in their 
nature. Inorganic salts, notably chloride of sodium, are especially abun- 
dant in air in the vicinity of salt water, and rarely is air so free from this 
salt that the flame of a Bunsen burner, when examined spectroscopically, 
does not show the sodium lines. 

Minute particles of the most heterogeneous substances float in air as 
dust, and become visible in the path of a ray of sunlight. The continued 
inhalation of air containing large quantities of such solid particles in sus- 
pension may cause severe pulmonary disorder by mere mechanical irrita- 
tion, and apart from any poisonous quality in the substance ; such is the 
case with the air of carpeted ball-rooms, and of the workshops of certain 
trades, furniture-polishers, metal-filers, etc. 

Air always contains varying quantities of vegetable germs, to which 
the phenomena of the so-called spontaneous generation are due, and 
concerning whose action in the propagation of disease so much has been 
7 



93 GENERAL MEDICAL CHEMISTRY. 

written and so little is known. By miasms are understood certain ill-de- 
fined, putrescible, volatile, or solid substances contained in air and evolved 
from unhealthy localities. 

The air o£ confined spaces in which human beings or animals are re- 
spiring is not only deteriorated by the production of carbon dioxide and 
consumption of oxygen (see p. 240), but also by the discharge into it of 
particles of organic matter prone to putrefaction. These emanations, even 
when derived from healthy persons, soon render the air foul, and their 
removal from spaces in which many people are congregated is one of the 
chief functions of ventilation. 



Ammonia. 

Hydrogen nitride — NH 3 — does not exist as such in nature. 

Obtained by decomposition of ammonium chloride, sulphate, or car- 
bonate, by slightly heating with dry slacked lime. In the laboratory, 
by heating aqua ammoniae, and drying the gas by passing it through a tube 
containing quicklime. At ordinary temperatures and pressure it is a 
colorless gas, having a penetrating odor ; irritating to the eyes and air- 
passages ; sp. gr. 0.589 A — 8.5H. ; exceedingly soluble in water, with 
which it enters into combination (see p. 409); at — 40° at the ordinary 
pressure, or at 10° under a pressure of six atmospheres, it forms a color- 
less, mobile liquid, which boils at — 33.7°; and at — 75° forms a colorless, 
transparent, crystalline mass, having but little odor. 

Ammonia is formed with difficulty by the union of its elements (see 
p. 95). When a mixture of hydrogen and one of the oxides of nitrogen 
is passed over heated platinum-sponge, reduction occurs, with formation 
of water and ammonia. If a mixture of sulphuric and nitric acids in 
proper proportion be poured upon zinc, there is no evolution of gas, 
although the zinc dissolves. In this reaction the hydrogen reduces the 
nitric acid with formation of an ammoniacal compound. 

Most organic substances containing nitrogen yield an ammoniacal 
compound, either by dry distillation, putrefaction, or the action of vapor 
of water, or of the caustic alkalies. 

Ammonia is decomposed — two volumes yielding one volume of nitrogen 
and three of hydrogen — by being heated to redness, or by the passage of 
the electric spark through it; by chlorine or bromine, with liberation 
of nitrogen (see Nitrogen Chloride); by iodine with formation of ex- 
plosive compounds of iodine and nitrogen; by the alkaline hypochlorites 
and hypobromites. 

Under ordinary conditions, ammonia is neither a supporter of combus- 
tion nor combustible; it may be made to burn, however, in an atmosphere 
of oxygen, and mixtures of ammonia with oxygen, with nitrogen mon- 
oxide, or with nitrogen dioxide, explode when fired by the passage 
through them of the electric spark. 

Potassium, when heated in an atmosphere of ammonia, replaces an 
atom of hydrogen with formation of potassium amide, KH 2 N. With 
silver nitrate, ammonia forms two compounds, differing from each other 
in the temperatures at which they are formed, and in the readiness with 
which they give off ammonia. With the acids ammonia unites directly 
to form ammoniacal salts (see p. 408). 

When inhaled, ammonia produces violent irritation of the respiratory 



NITROGEN MONOXIDE. 99 

organs, and a sense of suffocation. Care should be had in administering 
the vapor in fainting-fits, etc., as cases are recorded in which death has 
resulted from the use of too liberal doses. 



Nitrogen Monoxide. 

Nitrous oxide — Laughing-gas — Nitrogen protoxide, N„0. — Discov- 
ered in 1766, by Priestley; further studied by Sir Humphrey Davy, who 
observed its effects upon the economy when inhaled. 

Prepared by decomposing ammonium nitrate by heat: 

N0 3 (NH 4 )=N a O+2H a (X 

If the gas be desired pure — as it should always be when used as an anaes- 
thetic — the ammonium salt must be pure and dry, and, especially, free 
from chloride, lest the gas be contaminated with chlorine. The salt 
should be heated, not too quickly, and the temperature maintained be- 
tween 210° and 250°. Below the lower temperature the decomposition 
does not occur, and the salt sublimes; while, at temperatures above 250°, 
nitrogen dioxide and nitrogen trioxide are also formed. As an additional 
precaution, the gas should be caused to bubble through solutions of 
sodium hydrate and of ferrous sulphate, to arrest any higher oxides of 
nitrogen which mav be formed. 

Nitrogen monoxide is a colorless, odorless gas, having a sweetish 
taste; sp. gr. 1.527 A — 22H; somewhat soluble in water, more so in 
alcohol. Under a pressure of thirty atmospheres at 0°, it forms a colorless, 
mobile liquid, which boils at — 87.9°, and solidifies at — 100°. The 
liquefied gas, in suitable wrought-iron vessels, is obtainable from dental 
depots, and is used by dentists as a convenient source of the gas for use 
as an anaesthetic. 

Nitrogen monoxide is decomposed by a red heat, or by the continued 
passage of the induction spark. It is, after oxygen, the best supporter 
of combustion known, being readily decomposed into a mixture of oxygen 
and nitrogen, in which the former gas is in larger proportion than in at- 
mospheric air (36.36 per cent, by weight). 

The action of this gas upon the economy is of medical interest, from 
its use as an anaesthetic, and in connection with the history of anaesthesia. 
Although, owing to the readiness with which nitrogen monoxide is de- 
composed into its constituent elements, and the nature and relative pro- 
portions of these elements, it is capable of maintaining respiration longer 
than any gas or mixture of gases, except oxygen or air; an animal will 
live for a short time only in an atmosphere of pure nitrous oxide. When 
inhaled diluted with air, it produces the effects first observed by Sir 
Humphrey Davy in 1799: first an exhilaration of spirits, frequently ac- 
companied by laughter, and a tendency to muscular activity, the patient 
sometimes becoming aggressive: afterward there is loss of consciousness 
and complete anaesthesia. It has been much used, by dentists especially, 
as an anaesthetic in operations of short duration, and in one or two in- 
stances anaesthesia has been maintained by its use for nearly an hour. 

A solution in water underpressure, containing five volumes of the gas, 
is sometimes used for internal administration. 



100 GENERAL MEDICAL CHEMISTRY. 



Nitrogen Dioxide. 

Nitric oxide — NO. — Discovered by Hales in 1772. 
Prepared by the action of copper upon nitric acid: 

3Cu+SN0 3 H=3 (N0 3 ) 2 Cu + 4H 2 + 2NO. 

At first the flask in which the action takes place is filled with brown 
fumes, which gradually disappear; the gas is not collected until it has 
become colorless; the acid used should not be too concentrated, and should 
not be allowed to become heated. 

It is a colorless gas, whose taste and odor are unknown; sp. gr. 
1.039A — 15H; very sparingly soluble in water; more soluble in alcohol. 

When mixed with oxygen or air, it immediately unites with oxygen to 
form the tetroxide, which appears as a reddish brown gas. When passed 
through a solution of ferrous sulphate, it is absorbed by the liquid, to 
which it communicates a dark brown or black color. 

Although containing a greater proportion of oxygen than air or nitro- 
gen monoxide, it is not as good a supporter of combustion as either of 
those gases; although phosphorus burns in it brilliantly, and the alkaline 
metals unite with its oxygen with incandescence when heated in its 
presence. 

Nitrogen Trioxide. 

Nitrous anhydride — N 2 3 . — A substance not yet isolated in a state 
of purity, the purest yet obtained still containing about five per cent, of the 
tetroxide, from which it is obtained by decomposing with water at a low 
temperature: 

4N0 2 + H,0 = 2NO.H + N.O,. 

At ordinary temperatures it is a gas, whose properties are masked by 
the presence of the tetroxide; below the freezing-point of water it is a 
dark indigo-blue liquid, which, boiling at about 0°, suffers partial decom- 
position. 

Nitrogen Tetroxide. 

Nitrogen peroxide — Hyponitric acid — Nitrous fumes — N0 2 . — Formed 
whenever nitrogen trioxide comes in contact with oxygen. More read- 
ily, and in a condition of greater purity, by heating dry lead nitrate to 
redness, when nitrogen tetroxide is given off and lead oxide remains. 

Formed also indirectly when a metal is dissolved in nitric acid; and 
directly when nitric acid is brought in contact with a platinum surface 
heated to redness. 

This substance is remarkable for assuming when pure the three condi- 
tions of matter within a comparatively small range of temperature; above 
22° it is a gas; between that temperature and —9° it is a liquid; and below 
that a solid. The color of the liquid varies with the temperature, being 
of a light brown color at ordinary temperatures, and darkening as the 
point of solidification is approached. Nitrogen tetroxide is decomposed 



NITPwOGEN PENTOXIDE. 101 

by water with the formation of nitrous and nitric acids, and by the hy- 
drates of the alkaline and alkalo-earthy metals, with formation of a nitrite 
and a nitrate. 

Action on the Economy. 

The brown fumes given off during many processes, in which nitric 
acid is decomposed, consist largely of nitrogen tetroxide, and are not 
only offensive, but dangerous to life. All such operations, when carried 
on on a small scale, as in the laboratory, should be conducted under a 
hood or some other arrangement, by which the fumes are carried into the 
open air; when, in industrial processes, the volume of gas formed becomes 
such as to be a nuisance when discharged into the air, it should be ab- 
sorbed, either by utilizing it in the manufacture of sulphuric acid, or by 
causing it to be absorbed by water or an alkaline solution. 

An atmosphere contaminated with brown fumes is more dangerous 
than one containing chlorine, as the presence of the latter is more imme- 
diately annoying, while the former only produces its full effects some time 
after inhalation. 

Quite a number of fatal cases are recorded, usually resulting from the 
spilling of nitric acid and attempts on the part of the victim to pre- 
vent or repair damage caused thereby. At first there is only coughing, 
and it is only two to four hours later that a difficulty in breathing is felt, 
death occurring in ten to fifteen hours. At the autopsy the lungs are 
found to be extensively disorganized and filled with black fluid. 

Even air containing small quantities of brown fumes, if breathed for 
a long time, produces chronic disease of the respiratory organs. To pre- 
vent such accidents, thorough ventilation in locations where brown fumes 
are liable to be formed is imperative. In cases of spilling nitric acid, safety 
is to be sought in retreat from the apartment until the fumes have been 
replaced by pure air from without. 



Nitrogen Pentoxide. 

N~itric anhydride, N 2 5 . — Obtained by Deville, by decomposing dry 
silver nitrate with dry chlorine, the operation being aided by gentle heat, 
and conducted in an apparatus made entirely of glass, with ground joints; 
or, more readily, by the removal of water from fuming nitric acid by the 
action of phosphorus pentoxide. 

It forms prismatic crystals, which fuse at 30°, and boil at 47°. It takes 
up water with great eagerness, and gives off white fumes when exposed 
to the air, the result of its combination with water being nitric acid. 
Even when kept in sealed tubes at low temperatures, it decomposes slowly 
into oxygen and nitrogen tetroxide, the pressure of the gases formed being 
often sufficient to fracture the glass, although the pentoxide is not, strictly 
speaking, explosive. The decomposition is hastened by the action of heat 
or of light. Most substances which unite readily with oxygen remove 
that element from the pentoxide, the action being attended with the ap- 
pearance of light and heat. 



102 GENERAL MEDICAL CHEMISTRY. 

Nitrogen Acids. 

Three of these are known to exist, either free or in combination: 

Hyponitrous acid, Nitrous acid, Nitric acid, 

NOH, N0 2 H, N0 3 H, 

corresponding to the three oxides, which contain for two atoms of nitro- 
gen an uneven number of atoms of oxygen: 

N„0 +H 2 0=2NOH. 
N 2 3 + H 2 = 2N0 2 H. 
N 9 B +H,0=2N0 8 H. 

Hyponitrous acid, NOH. — Obtained by E. Divers, in 1871, as its sil- 
ver salt, by the action of nascent hydrogen on sodium nitrate, and precip- 
itation with silver nitrate; and in aqueous solution, by decomposing the 
silver salt with the proper quantity of hydrochloric acid; as yet only of 
theoretical interest. 

Nitrous acid, N0 2 H. — Although this acid has not yet been isolated 
in a state of purity, there exist, corresponding to it, a series of well-defined 
salts called nitrites, having the composition NO a M' or (N0 2 ) 2 M". 

Nitric Acid. 

Acidum nitricum ( XT. S., Br.) — Aquafortis — N0 3 H. — Known to the 
earlier alchemists as aqua prima, aqua fort is, or spirits of nitre. Its true 
nature was first recognized by Cavendish, in 1784. It does not exist free 
in nature, but is abundant and widely disseminated in its salts, the nitrates. 

Nitric acid is formed, naturally and artificially, in the process known 
as nitrification (q. v.), by the decomposition of nitrogenized organic ma- 
terials. It is also formed by the passage of electric discharges through a 
mixture of nitrogen and oxygen, a formation which takes place naturally 
in the atmosphere, to a limited extent. Under certain conditions, it is also 
formed by the action of air upon ammonia, and by the oxidation of nitro- 
gen or of ammonia by ozone. 

The nitric acid used in the arts is, however, exclusively obtained by 
the decomposition of the nitrates of sodium and of potassium by sulphuric 
acid: 

N0 3 Na + S0 4 H 2 = S0 4 HNa + N0 3 H, 

the decomposition being conducted by the aid of heat in cast-iron vessels, 
from which the vapors are conducted through earthenware bottles in which 
the nitric acid condenses. The acid so formed is still largely charged with 
brown fumes, chlorine, and sulphuric acid, from which it is separated by 
heating to 80°, and by rectification over lead nitrate. 

The pure acid, having the composition N0 3 H, is a colorless, rather 
heavy liquid; sp. gr. 1.52; boils at 86°; solidifies at —40°; gives off white 
fumes in damp air; has a strong acid taste and reaction, and destroys 
organic matters. The specific gravity and the boiling-point of acids of 
less strength differ with the amount of true nitric acid which they con- 
tain; the following table, partly from Willm's article in Wurtz' "Diet. d. 
Chimie," and partly from Kolb, indicates these variations. 



NITRIC ACID. 



103 



QUANTITY OF TRUE NO s H IN NITRIC ACIDS OF DIFFERENT 

DENSITIES. 



Density. 


Degree Baumd 


Per cent, water. 


Per cent. N0 3 H. 


Boiling-point. 


1.522 


49.3 




100.00 


86° 


1.486 


46.5 


11.25 


88.75 


99° 


1.452 


45.0 


22.22 


77.78 


115° 


1.420 


42.6 


30.00 


70.00 


120° 


1.390 


40.4 


36.36 


63.64 


119° 


1.361 


38.2 


41.67 


58.33 


117° 


1.338 


36.5 


46.16 


53.84 




1.315 


34.5 


50.00 


50.00 


113° 


1.297 


33.2 


53.33 


46.67 




1.277 


31.4 


56.25 


43.75 




1.260 


29.7 


58.82 


41.18 


m m 


1.245 


28.4 


61.11 


38.89 




1.232 


27.2 


63.16 


36.84 




1.219 


25.8 


65.00 


35.00 




1.207 


24.7 


66.67 


33.33 


108° 


1.197 


23.8 


68.18 


31.82 




1.188 


22.9 


69.56 


30.44 




1.180 


22.0 


70.83 


29.17 




1.173 


21.0 


72.00 


28.00 




1.166 


20.4 


73.08 


26.92 




1.160 


19.9 


74.07 


25.93 




1.155 


19.3 


75.00 


25.00 


about 104° 


1.138 


17.6 


77.00 


23.00 




1.120 


15.4 


80.00 


20.00 


m ^ 


1.101 


13.1 


82.56 


17.44 




1.089 


11.8 


85.00 


15.00 


... • 


1.068 


9.4 


88.57 


11.43 




1.022 


2.8 


96.00 


4.00 




1.010 


1.4 


98.00 


2.00 





It will be observed that the boiling-point at first increases and then dimin- 
ishes with dilution. If a strong acid be distilled, the boiling-point will 
gradually increase until it readies about 123°, when it will remain con- 
stant, the density of distilled and distillate at this point being about 1.42; 
if, on the other hand, a weaker acid be taken originally, the boiling-point 
will rise until it reaches the same point, where it remains constant. 

If heated to redness, the vapor of nitric acid is decomposed into nitro- 
gen tetroxide, water, and oxygen. The same change takes place when 
the acid is exposed to light and air at ordinary temperatures; it is from 
this cause that nitric acid in partially filled bottles, exposed to the light, 
assumes a yellowish tinge. Nitric acid gives up its oxygen readily, and 
is thus a valuable oxidizing; anient. Most of the metalloids are oxidized 
by it, and lower are converted into higher stages of oxidation. It also 
oxidizes many organic substances, and with others forms products of sub- 
stitution. Copper, silver, and mercury are dissolved in nitric acid, espe- 



104 GENERAL MEDICAL CHEMISTRY. 

cially under the influence of heat, with formation of nitrates and evolution 
of nitrogen dioxide, which, combining with atmospheric oxygen, forms 
brown fumes: 

4NO t H+3Ag=3NO,Ag+NO + 2H t O. 

The action between nitric acid and iron is peculiar; a weak acid dissolves 
the metal readily, with evolution of brown fumes; but a strong acid not 
only does not dissolve it, but renders it passive, so that when it is trans- 
ferred from the strong to a weak acid no action takes place until the pas- 
sive condition of the iron is destroyed by touching it with a piece of plati- 
num wire, or by other means. When nitrogen dioxide and nitric acid 
come together they decompose each other, with formation of the tetroxide: 

2N0 3 H + NO = 3N0 2 + H a O, 

the tetroxide being in turn decomposed, in presence of the water of the 
acid, into nitric acid and the trioxide: 

4N0 2 -fH 2 0=2N0 3 H + N 2 3 , 

the latter being dissolved in the acid, to which it communicates a yellow, 
brown, or green color. An acid so charged with the trioxide, sometimes 
called nitrosonitric acid, is obtained by acting upon nitric acid, with cop- 
per or iron, or preferably, by connecting the terminals of one or more cells 
of a Grove battery, and removing the acid from the porous cup after the 
action has continued for half an hour. 

Nitric acid oxidizes hydrochloric acid when brought in contact with 
it, with liberation of free chlorine or of compounds of chlorine, oxygen, and 
hydrogen. A mixture of three parts of hydrochloric acid with one part 
of nitric acid, both of commercial strength, is a reddish yellow liquid, 
known as aqua regia, which, in the presence of bodies capable of uniting 
with chlorine, is a source of that element in the nascent state. 

Nitric acid occurs in commerce and in pharmacy in the following 
forms : 

Commercial, a yellowish liquid, contaminated with oxides of nitro- 
gen, hydrochloric acid, arsenic and other impurities, should never be 
used medicinally, or for any but rough chemical purposes. It is of two 
strengths; single aquafortis, specific gravity about 1.25, and double aqua 
fortis, specific gravity about 1.4. 

Fuming. — A reddish yellow fluid, of sp. gr. 1.525, highly charged 
with nitrogen trioxide (and tetroxide ?), more or less free from impurities, 
according 1 to the care exercised in its manufacture. Used as an oxidizing" 
agent. 

C. P., or chemically pure — perfectly colorless, sp. gr. 1.522. A por- 
tion evaporated on platinum should leave no residue. When diluted 
with two volumes of distilled water it should give no cloudiness with 
barium chloride (sulphuric acid), or with silver nitrate (chlorine). Chloro- 
form, when shaken with the diluted acid, should not be colored, even 
after the addition of a few drops of solution of hydrogen sulphide (iodine). 
Solution of potassium permanganate should not be decolorized when 
added to the dilute acid (oxides of nitrogen). When evaporated over 
the water-bath to small bulk, the residue, diluted with water, should not 
give any colored precipitate when treated with hydrogen sulphide 
(metals). 



ACTION ON THE ECONOMY. 105 

For analytical processes only an acid responding to these tests, or a 
fuming 1 acid responding to all except those for the oxides of nitrogen, 
should be used. An impure acid may be purified by distilling and reject- 
ing the first quarter of its bulk, adding to the remainder excess of silver 
nitrate and barium nitrate, and distilling in an apparatus of glass. 

Acidum nitricum (V. S., Br.). — An acid of sp. gr. 1.42, containing 
70$ N0 3 H, and free from impurities other than water. 

Acidum nitricum dilutum ( IT. S., Br.), the last mentioned, diluted 
with water to sp. gr. 1.068 = 11.43$ N0 3 H (Z/>. &), or sp. gr. 1.101 = 
17.44$ N0 3 H (Br.). 

Nitric acid should be kept in bottles completely filled and protected 
from the light. 

Analysis — The presence of nitric acid, or of a nitrate, may be detected 
by the following tests: 

First. — Add to the liquid an equal volume of concentrated sulphuric 
acid, cool, float upon the surface of the mixture a small quantity of a 
solution of ferrous sulphate; if nitric acid or a nitrate be present, the 
lower layer is after a time colored, beginning at the top, black, brown, 
or reddish purple, according to the quantity of acid present. 

Second. — Boil in a test-tube a small quantity of hydrochloric acid 
containing enough solution of sulphindigotic acid to communicate a blue 
color; if now nitric acid or a solution of a nitrate be added, and the mix- 
ture again boiled, the color is discharged. 

Third. — If acid, neutralize with an alkali, evaporate to dryness, add 
to the residue a few drops of sulphuric acid and a crystal of brucia; a red 
color is communicated to the alkaloid by nitric acid. In place of brucine, 
sulphanilic acid may be used. 

Fourth. — Heat the suspected solution (to which, in the case of a nitrate, 
concentrated sulphuric acid has been added) with copper turnings in a 
test-tube; if nitric acid be present, brown fumes will appear, best visible 
by looking into the mouth of the tube. 

All neutral nitrates are soluble in water; some so-called basic salts are 
insoluble, as bismuthyl nitrate, N0 3 (BiO). 



Action on the Economy. 

Nitric acid cannot be said to be a true poison, for, although most of 
the nitrates exert a poisonous action when taken internally, that action 
seems to be due more to the metal than to the acid radical. Nitrates 
have also been found to be, although in very small quantity, normal 
constituents of the urine. 4 

The acid is, however, one of the most powerful of corrosives; any 
animal tissue with which it comes in contact is immediately disintegrated; 
a yellow stain, afterward turning to dirty brownish, or, if the action be 
prolonged, an eschar, is formed. When taken internally its corrosive 
action is the same as that which follows its application to the cutaneous 
surface, but, owing to the function of the parts, is followed by more 
serious results. As is the case with the other mineral acids, it is rarely 
administered with intent to murder, but is frequently taken by suicides, 
or by mistake by children or inebriates. The symptoms following its in- 
gestion are the same as those appearing with the other corrosive acids, 
with the exception that the mouth and any other parts with which the 
acid may have come in contact, as well as shreds of detached mucous 



106 GENERAL MEDICAL CHEMISTRY. 

membrane in the vomited matters, are stained yellow, which is not the 
case when sulphuric or hydrochloric acid has been taken. 

The treatment is the same as in corrosion by sulphuric or hydrochloric 
acid, i. e., neutralization by magnesia, or, failing that, by alkalies, as 
rapidly as possible, and a subsequent sustaining treatment. 



Compounds of Nitrogen -with Elements of the Chlorine Group. 

Nitrogen chloride, NC1 3 , obtained by the action of chlorine gas, in 
excess, upon ammonia or upon an ammonium compound, or by the elec- 
trolysis of a strong solution of ammonium chloride; usually, by confining 
chlorine over a solution of ammonium chloride. An oily, light yellow liquid, 
sp. gr. 1.653; has been distilled at 71°; but when heated to 96°, when 
subjected to concussion, or when brought in contact with phosphorus, 
spirits turpentine, alkalies, oils, or grease, etc., it is decomposed into one 
volume of nitrogen and three volumes of chlorine, the decomposition 
being attended with a violent explosion. Owing to the force which this 
explosion exerts, great care should be had that the conditions for the for- 
mation of nitrogen chloride should not be fulfilled. If by accident, the 
substance be formed, the laboratory should be closed and abandoned for 
a few days, during which the chloride will suffer spontaneous decompo- 
sition. 

Nitrogen bromide — NBr 3 — has been obtained as a reddish brown, 
syrupy liquid, very volatile, and resembling the chloride in its properties, 
by the action of potassium bromide upon nitrogen chloride. 

Nitrogen iodide, NI 3 . — When iodine is brought in contact with ammo- 
nium hydrate solution, a dark brown or black powder, highly explosive 
when dried, is formed. This substance varies in composition according 
to the conditions under which the action occurs; sometimes the iodide 
alone is formed; under other circumstances it is mixed with compounds 
containing nitrogen, iodine, and hydrogen. 



PHOSPHORUS. 



31 



Discovered in 1669, by Brandt, of Hamburg, while searching for the 
philosopher's stone in urine. Brandt, however, kept his process a secret, 
and the discovery was subsequently repeated by Kunckel and by Boyle. 
In 1769, Gahn detected its existence in bones, and Scheele suggested a 
process for obtaining it from this source. It does not exist in nature in 
its elementary form, but exclusively in phosphates and in certain organic 
substances. 

Phosphorus is obtained from bone-ash. in which it exists as tricalcic 
phosphate (q. v.); this, by treatment with sulphuric acid, is converted 
into the soluble monocalcic phosphate — 

(P0 4 ) 2 Ca 3 + 2S0 4 H 2 == (P0 4 ) 2 CaH 4 + 2S0 4 Ca, 

which is separated by solution, decantation, and evaporation, from the calcic 
sulphate. The phosphate is then mixed with about one-fourth its weight 
of powdered charcoal and sand, and dried to such an extent that about five 



PHOSPHO RUS. 107 

per cent, of water is retained. The dried mixture is introduced into clay 
retorts, whose beaks dip underwater contained in a suitable receiver; the 
retorts are heated, to redness at first, and finally to a white heat. Dur- 
ing the first portion of the heating, the monocalcic phosphate is converted, 
by loss of water, into the metaphosphate — 

(POJ a CaH 4 = (PO,),Ca+2H s O, 

and this is in turn reduced by the charcoal, while the silicon dioxide re- 
moves the calcium as silicate: 

2(PO 3 ),Ca-|-2SiO 2 + 5C 2 =2SiO 3 Ca+10CO + P 4 . 

The crude product so obtained is purified either by redistillation, or by 
fusing it under warm water, and oxidizing the impurities with a small 
quantity of sulphuric acid and potassium dichromate. Finally, the phos- 
phorus is cast into glass moulds, under water. 

Phosphorus exists in two distinct allotropic conditions, which differ 
from each other materially in their physical properties, as well as in the 
activity of their chemical actions. 

The ordinary variety, also known as white, and formerly as crystalliz- 
able phosphorus, is that obtained by the process described above. It is 
a colorless or yellowish, translucid solid, of about the consistency of wax. 
Below 0° it is brittle ; it melts at 44°. 3, and boils at 290° in an atmos- 
phere not capable of acting upon it chemically, being converted into a 
colorless gas whose specific gravity is 4.3A — 61.1 H. It gives off vapors 
at temperatures below its boiling-point, and when water is boiled upon 
it the aqueous vapors are charged with its vapor. The specific gravity of 
the solid is 1.83 at 10°. When exposed to the air it gives off white 
fumes, and the odor of ozone is observed. In the dark it produces a 
peculiar pale light, and to this property it owes its name of " light 
bearer" (<£d>s-<£epco). It is insoluble in water and in alcohol, soluble in 
carbon disulphide, benzine, petroleum, ether, and in the fixed and essen- 
tial oils. Its solutions on evaporation leave it in the form of octahedral 
or dodecahedral crystals, in which latter form it may also be obtained by 
the solidification of fused phosphorus. 

The red variety is obtained from the white by maintaining the latter 
at a temperature of about 250°, for thirty-six hours or more, in an atmos- 
phere of carbon dioxide, and washing the residue with carbon disulphide 
as long: as anything* is dissolved. 

It is an odorless, tasteless solid, which does not fume when exposed 
to the air, and is not soluble in the solvents of the ordinary variety. Its 
color and density depend upon the temperature at which it was formed ; 
it is usually brownish red, and of sp. gr. 2.1. When heated to the 
temperature of its formation it does not melt, but at a slightly higher 
temperature is converted into the white variety, which either ignites or 
distils according: to the conditions under which the conversion occurs. 
The red variety may also be obtained in the crystalline form, but not as 
readily as white phosphorus. 

Besides these two forms, there are others which are by some authors 
considered as distinct allotropic varieties. One of these is formed as a 
white crust, when the ordinary phosphorus is exposed, under water 
holding air in solution, to diffuse daylight. Another form, called black 
phosphorus, is produced when ordinary phosphorus, which has been 
repeatedly distilled, is heated to 70° and cooled suddenly. 



108 GENEFwAL MEDICAL CHEMISTRY. 

One of the most prominent properties of phosphorus is the readiness 
with which it unites with oxygen. If ordinary phosphorus be heated in 
contact with air to 00°, or if it be exposed in a finely divided state to air at 
the ordinary temperature, it ignites and burns with a bright flame, giving 
off dense, white clouds of phosphorus pentoxide ; it may even be burned 
under water heated above its fusing-point, by causing a current of oxy- 
gen to come in contact with it. The readiness with which white phosphorus 
fires, and the serious nature of the burns caused by it (see below), render 
the greatest caution necessary in handling it ; it must always be kept 
under water (it is best to use boiled water and to keep the bottle in the 
dark) ; it should never be brought in contact with the skin except under 
water, and when it is to be cut, this should be done under water. If 
desired in a finely divided condition, it may be fused in warm water 
(water holding urea in solution is better than pure water) and shaken 
until it has solidified by the cooling of the water. 

The red variety does not unite with oxygen so readily, and may be 
kept exposed to the air and handled with impunity. When exposed to 
damp air it oxidizes slowly, but does not become luminous in the dark. 

Either variety unites readily with chlorine, bromine, and iodine, with 
formation of chlorides, bromides and iodides (q. v.) The union of these 
elements with the white variety is attended with the liberation of heat 
and of light. Most other elements are capable of uniting directly with 
phosphorus; hydrogen, nitrogen and carbon are not. Many salts are re- 
duced by white phosphorus. When immersed in a solution of cupric sul- 
phate the surfaces of a fragment of phosphorus became coated with 
metallic copper; in a solution of silver nitrate the surface of the phos- 
phorus becomes blackened by the deposition upon it of the black silver 
phosphide. 

Action on the Economy. 

The two varieties of phosphorus differ from each other in the impor- 
tant particular that, while the red phosphorus is practically inert when 
taken internally — probably owing to its insolubility — and is but little 
liable to give rise to burns, the white variety is actively poisonous, and, 
when ignited in contact with the skin, produces very painful wounds, 
whose effects are serious beyond what could be expected from the mere 
local injury produced. A burning fragment of white phosphorus adheres 
tenaciously to the skin, into which it burrows in burning. One of the 
products of the combustion is metaphosphoric acid, which, being absorbed, 
gives rise to true poisoning (see p. 115). Cases are not wanting in which 
death has followed burns by phosphorus, of an extent which would not 
be serious if caused by the combustion of other substances. Burns by 
phosphorus should be washed immediately with dilute Javelle water, liq. 
sod. chlorinatse, or solution of chloride of lime. 

When taken internally, phosphorus (the ordinary variety) is one of 
the most insidious of poisons, and one w r hich, on the continent of Europe, 
has of late years become the favorite agent in homicidal poisoning — the 
average number per annum of cases of criminal poisoning by phosphorus 
in Paris being greater than that of cases of the same nature, in which 
arsenic was used. Whether such cases are of frequent or rare occurrence 
in the United States, it is difficult to determine, from the meagre and un- 
reliable statistics at hand. Certain it is that the number of accidental and 
suicidal deaths from phosphorus and " rat-poison," noted in the reports 



ACTION ON THE ECONOMY. 109 

of the New York Board of Health for the past ten years, would indicate 
that the toxic nature of these substances is not unknown among our popu- 
lation. 

The substances generally used are match-heads, or "rat's bane" — the 
former being in the ordinary sulphur match, a mixture of potassium 
chloride, very fine sand, phosphorus, and a coloring matter, Prussian blue 
or vermilion ; and the latter a paste of flour charged with phosphorus. 
It is not improbable that the recently introduced medicinal preparations 
of phosphorus may produce fatal poisoning in the future. The symptoms 
in acute phosphorus-poisoning appear with greater or less rapidity, ac- 
cording to the dose, and the presence or absence in the stomach of sub- 
stances which favor its absorption. Their appearance may be delayed 
for days, but as a rule they appear within a few hours. A disagreeable, 
garlicky taste in the mouth, and heat in the stomach are first observed, the 
latter gradually developing into a burning pain, accompanied by vomiting 
of dark-colored matter, which, when shaken in the dark, is phosphores- 
cent ; low temperature and dilatation of the pupils. In some cases death 
follows at this point suddenly, without the appearance of any further 
marked symptoms ; usually, however, the patient rallies, seems to be 
doing well, until suddenly jaundice makes its appearance, accompanied 
by retention of urine, and frequently delirium, followed by coma and 
death. 

There is no known chemical antidote to phosphorus ; the treatment 
is, therefor, limited to the removal of the unabsorbed portions of the 
poison by the action of an emetic, zinc sulphate or apomorphia, as expe- 
ditiously as possible, and the administration of oil of turpentine — the 
older the oil the better — as a physiological antidote. The use of fixed 
oils or fats is to be avoided, as they favor the absorption of the poison 
by their solvent action. The prognosis is very unfavorable. 

As commercial phosphorus is usually contaminated with arsenic, the 
effects of the latter substance may also appear in poisoning by the former. 

Analysis. — When, after a death supposed to be caused by phos- 
phorus, chemical evidence of the existence of the poison in the body, etc., 
is desired, the investigation must be made as soon after death as possi- 
ble, for the reason that the element is rapidly oxidized, and the detection of 
the higher stages of oxidation of phosphorus is of no value as evidence of 
the administration of the element, because they are normal constituents 
of the body and of the food. 

The detection of elementary phosphorus in a systematic toxicological 
analysis is connected with that of prussic acid, alcohol, ether, chloroform, 
and other volatile poisons. The method adopted should be a combination 
of the processes of Mitscherlich, Blondlot, and Neubauer and Frezenius. 
Mitscherlich's process would be sufficient of itself were it not that the 
power of phosphorescence of phosphorus is held in abeyance by the 
presence of alcohol or ether, and is permanently destroyed by admixture 
of oil of turpentine, the last-named substance being one which is very 
liable to be mixed with the contents of the stomach, if the case have been 
recognized as one of phosphorus-poisoning before death. 

The substances to be examined, usually the contents of the stomach 
(the other volatile poisons should be looked for first in the lungs), are 
diluted with water, acidulated with sulphuric acid, and heated in a flask 
over the sand-bath. The flask is connected by a perforated cork and a 
long, bent tube, with a Liebig's condenser placed in a vertical position and 
in absolute darkness, and so arranged as to deliver the distillate iuto a 



110 GENERAL MEDICAL CHEMISTRY. 

suitable receiver, while through the entire apparatus a current of carbon 
dioxide is made to pass. The odor of the distillate is noted. If phos- 
phorus be present, it is usually garlicky. The condenser is also observed. 
If at the point of greatest condensation a faint, luminous ring be observed 
(in the absence of all reflections), it is proof positive of the presence of 
unoxidized phosphorus; the absence, however, of that poison is not to be 
inferred from the absence of the luminous ring. If this fail to appear 
when one-third the fluid contents of the flask have passed over, the re- 
ceiver is removed (its contents being reserved for the detection of the 
more volatile poisons), and in its place are arranged two V-tubes, or a 
Liebig's bulb-tube filled with neutral solution of silver nitrate. If phos- 
phorus be present, either in its own form or in its lower stages of oxida- 
tion, a black deposit of silver phosphide is formed; if no blackening 
of the silver solution occur, the absence of phosphorus may be inferred. 
If blackening have occurred, the deposit is introduced into the generator 
of an apparatus furnishing pure hydrogen (see Zinc), which, after drying 
over sulphuric acid, is burned as it issues from a platinum jet. If the black 
deposit be silver phosphide, the inner portion of the flame will be bright 
green, and will exhibit the characteristic green lines of phosphorus when 
examined spectroscopically. 

Chronic poisoning by phosphorus. — This form of poisoning, also known 
as the Lucifer disease, occurs among operatives engaged in the dipping, 
drying, and packing of phosphorus matches. Sickly women and children 
are most subject to it. Workmen in factories where the element itself 
is produced are not affected. The cause of the disorder is variously 
ascribed to the contamination of phosphorus with arsenic, and to the 
presence in the atmosphere of oxides of phosphorus and ozone. The prog- 
ress of the disease is slow, and its most prominent and culminating mani- 
festation is the destruction of one or both maxillae by necrosis. 

The frequency of the disease may be in some degree diminished by 
maintaining a thorough ventilation of the shops, by frequently washing 
the face and rinsing the mouth with a weak solution of sodium carbonate, 
and by exposing oil of turpentine in saucers in the workshops. By none 
of these methods, however, will the prevention of the disease be perfect — 
a result which can only be attained by abandoning the use of white 
phosphorus, for the manufacture of matches, entirely. The increased 
cost of red phosphorus is of no weight against the advantages of prevent- 
ing this fearful disease, and at the same time removing from the reach 
of the poisoner one of the most potent and easily obtained of toxic agents. 



Hydrogen Phosphides. 

There exist no less than three compounds of hydrogen and phospho- 
rus, of which the most important is the one corresponding in composi- 
tion to ammonia. 

Gaseous hydrogen phosphide — Phosphonia — Phosphamine — PH 3 — a 
gaseous substance, two volumes of which contain half a volume of vapor 
of phosphorus and three volumes of hydrogen. 

It is formed in a number of reactions, but can only be obtained in a 
state of purity by the decomposition of phosphonium iodide, PH 4 I, by 
water, or by solutions of the alkalies. As thus obtained, it is a colorless 
gas, having a strong alliaceous odor, very sparingly soluble in water j 



OXIDES OF PHOSPHORUS. Ill 

sp. gr. 1.134A — 17.5H. It fires at about 70°, or on contact with fum- 
ing nitric acid, chlorine, bromine, or iodine. 

The methods usually employed for obtaining the gas are, by heating 
phosphorus with a strong solution of potassium hydrate, or with thick 
milk of lime ; or by decomposing calcium phosphide by water. When 
prepared by these methods the gas differs from the pure substance, in 
that as each bubble comes in contact with air it takes fire spontaneously, 
with the formation of a white ring of phosphorus pentoxide; this property 
it owes to the presence of traces of another compound (see below). 

The impure gas is also formed during the putrefaction of organic sub- 
stances containing phosphorus. The natural phenomenon of ignis fatuus, 
or Will o' the Wisp, is probably due to such a formation of hydrogen 
phosphide. 

The gas is highly poisonous, even when the air contains less than one 
per cent. Its poisonous action is due to its oxidation at the expense of 
the blood-coloring matter, whose destruction produces death by asphyxia. 
After death the blood is found to be dark, to have a violet tinge, and to 
have, in a^reat measure, lost its capacity for absorbing oxygen. 

Liquid hydrogen phosphide — P 2 H 4 — is the substance whose vapor 
communicates to PH 3 its property of spontaneously igniting on contact 
with air. It may be obtained by passing the gas, obtained by the decom- 
position of calcium phosphide by water, through a bulb-tube enclosed in 
a freezing mixture. 

It is a colorless, heavy liquid, readily decomposable at a temperature 
of 30°, and by other influences which also destroy the spontaneous in- 
flammability of the gaseous product. 

Solid hydrogen phosphide — P 4 H 2 . — A yellow solid, formed by the de- 
composition of P 2 H 4 , under the influence of sunlight. It is not phos- 
phorescent, and only ignites when heated to 160°. 



Oxides of Phosphorus. 

These are two in number: 

Phosphorus trioxide P 2 3 * 

Phosphorus pentoxide P 2 5 « 

Phosphorus trioxide — Phosphorus anhydride — P 2 3 — is formed, as a 
white solid, when phosphorus is burned in a limited supply of dry air or 
oxygen. When exposed to moist air it is fired by the heat developed by 
its union with water to form phosphorous acid. 

Phosphorus pentoxide — Phosphoric anhydride — P 2 5 — is formed 
whenever phosphorus is caused to burn, in the absence of water, and in 
the presence of an excess of oxygen. It is a white, flocculent solid, which 
exhibits almost as great a tendency to unite with water as does the lower 
stage of oxidation. 

When exposed to the air it absorbs moisture rapidly, with liberation 
of heat and formation of a highly acid liquid, which does not contain or- 
thophosphoric acid, as we should expect from analogy, but metaphosphoric 
acid (q. v.). It is frequently used in the laboratory as a very energetic 
drying agent. 



112 GENERAL MEDICAL CHEMISTRY. 



Phosphorus Acids. 

These form a series of great interest from a theoretical point of view. 
The first has no corresponding oxide; the second is the hydrate of the tri- 
oxide, and the other hydrates are referable, directly or indirectly, to the 
pentoxide: 

Hypophosphorous acid P0 2 H 3 . 

Phosphorous acid P0 3 H 3 . 

Orthophosphoric acid P0 4 H 3 . 

Pyrophosphoric acid P 2 7 H 4 . 

Metaphosphoric acid P0 3 H. 

The basicity of these acids is also of interest. While P0 3 H is mono- 
basic, and P 2 7 H 4 is tetrabasic, all of their hydrogen atoms being replace- 
able — the other three, although each containing three atoms of hydrogen, 
vary in basicity: P0 2 H 3 is monobasic; P0 3 H 3 , dibasic; and P0 4 H 3 , tribasic. 



Hypophosphorous Acid — PO a H 3 , 

Is obtained as a strongly acid, colorless, syrupy liquid, by decomposing 
its barium salt with an equivalent quantity of sulphuric acid, filtering 
and concentrating the solution. It may also, with proper precautions, 
be obtained in the crystalline form. It is quite unstable, and, when ex- 
posed to the air, is oxidized into a mixture of phosphorous and phosphoric 
acids. Its salts are more stable, and some are used in medicine; they have 
the composition P0 8 H 2 M' or (P0 2 H 2 ) 2 M". 



Phosphorous Acid — P0 3 H 3 , 

Is best prepared by the decomposition of phosphorus trichloride by 
water, according to the equation: 

PC1 3 + 3H 2 = P0 3 II 3 + 3HC1. 

The hydrochloric acid formed is driven off by evaporation and by ex- 
posure over quicklime. The product is finally concentrated over sulphuric 
acid. It is also formed by exploding a mixture of phosphonia and oxygen, 
in the proportion of two volumes of the former to three volumes of the 
latter. It is a syrupy and highly acid liquid, readily decomposable by 
heat. It is an energetic reducing agent, taking up oxygen to form 
phosphoric acid. It forms salts called phosphites, whose composition is 
P0 3 HM1I, PO.HM',, or P0 3 HM". 

It has been stated that this acid is formed in concentrated aqueous 
solution, when phosphorus is exposed to the slow action of moist air; but 
from the recent researches of P. Salzer it would seem that the solution 
so obtained contains a new acid, which he calls hypophosphoric acid, and 
to which he ascribes the formula PO,H 2 (?). 



PYKOPHOSPHORIC ACID. H3 



Orthophosphorie Acid. 

Common, or tribasic phosphoric acid, P0 4 H 3 . — This acid, although 
not existing free, is widely disseminated in the three kingdoms of nature 
in its salts, the phosphates. 

It is usually obtained by the oxidation of phosphorus by dilute nitric 
acid, under the influence of heat. The action is liable to become violent, 
and the process should always be conducted with caution; indeed, it is 
best to use the red phosphorus in place of the ordinary variety. This is 
the process adopted (with subsequent dilution) in the United States and 
British Pharmacopoeias, to obtain the Acid, phosph. dilutum (see Meta- 
phosphoric Acid), enough nitric acid being used to oxidize the phos- 
phorus completely, and the excess being driven off by heat. The strength 
of the United States preparation is 10.21 per cent., P0 4 H 3 ; sp. gr., 
1.056; that of the British 14.42 per cent,, P0 4 H 3 ; sp. gr., 1.08? 

In the arts phosphoric acid is now usually obtained directly from bone 
ash, by converting the calcium phosphate contained in them into lead 
or barium phosphate; the insoluble compound is removed and decom- 
posed by hydrogen sulphide in the first case, and by sulphuric acid in 
proper proportion in the second. 

It is also formed in other reactions, as by passing chlorine into phos- 
phorus melted under water, when phosphorus pentachloride is formed 
and immediately decomposed into phosphoric and hydrochloric acids; the 
latter is removed by evaporation. 

The concentrated acid usually is a colorless, transparent, syrupy fluid, 
which still contains water, and, by exposure over sulphuric acid, yields 
the pure acid in the form of transparent, prismatic crystals, which, on 
exposure to air, rapidly deliquesce, forming a highly acid, syrupy solution. 

For the action of heat on this acid, see below ; for tests (see p. 114). 
It forms many salts, whose composition is: PO H M'; PO HM' ; PO M' ; 
(POJ.M",; (PO.H),M", ; (P0 4 H,),M"; or P0 4 M'M". 

Phosphoric acid made from arsenical phosphorus (commercial phos- 
phorus is usually arsenical), is contaminated with arsenic trioxide, whose 
presence may be recognized by the application of Marsh's test (p. 129) 
to the aqueous solution. The aqueous acid should, on evaporation, leave 
no residue ; and should not respond to the indigo or ferrous sulphate 
tests for nitric acid. 



Pyrophosphoric Acid — P 2 7 H 4 . 

When orthophosphorie acid (hydrodisodic phosphate) is maintained 
for some time at a temperature of 213°, two of its molecules unite, 
with loss of the elements of one molecule of water, to form a new acid — 
pyrophosphoric acid, so called from its igneous origin: 

2P0 4 H 3 =P 2 7 H 4 +H 2 0. 

The acid is obtained free as a transparent, vitreous, semi-crystalline, 
soft mass, by decomposing its lead salt with hydrogen sulphide, filtering 
and concentrating the filtrate. It is tetrabasic. 
8 



114 GENERAL MEDICAL CHEMISTRY. 



Metaphosphoric Acid. 

Glacial phosphoric acid, P0 3 H. — This acid, whose composition is 
similar to that of nitric acid, is formed by the action of heat, approaching 
redness, on either ortho- or pyrophosphoric acid. In either case there is 
loss of the elements of a molecule of water : 

P0 4 H 3 -H 2 0=P0 3 H. 
P 2 ? H 4 -H a O=2P0 3 H. 

It is usually obtained directly from bone-ash, whose calcium phos- 
phate is first converted into ammonium phosphate, which is then sub- 
jected to a red heat. This is the process adopted by the United States 
Pharmacopoeia in obtaining the Acid, phosphoricum glaciale (see p. 115). 

It appears as a white, glassy, transparent solid, odorless, and having 
a sour taste. Slowly deliquescent when exposed to the air, it is very 
soluble in water, the solution taking place quite slowly, and being ac- 
companied by a peculiar crackling sound at intervals. 



Analytical Characters of the Phosphoric Acids. 

The three acids, P0 4 H 3 , P 2 7 H 2 , and P0 3 H, although closely related 
and all derived from the oxide P 2 5 , differ materially in their properties, 
and may, in solution of the free acids or of their salts, be distinguished 
from each other by the following reactions : 

Orthophosphoric acid. Pyrophosphoric acid. Metaphosphoric acid. 

With Ammoniacal Solution of Silver Nitrate. 
A yellow precipitate. A white precipitate. A white precipitate. 

With Solution of Albumen. 
No effect. No effect. Coagulation. 

With Solution of Ammonium Molybdate in Nitric Acid. 
A yellow precipitate. No effect. No effect. 

With Solution of Magnesium Sulphate in the Presence of Ammonium Chloride and 

Hydrate. 

A white, crystalline precipi- A white precipitate ; solu- No effect ; or a precipitate 

tafce; insoluble in ammo- ble in excess of phos- soluble in ammonium chlo- 

nium hydrate, nearly so phate or of magnesium ride, 

in ammonium chloride ; sulphate, 
soluble in acids. 

The last two reactions are only of value in the absence of arsenic acid. 

The quantitative determination of phosphoric acid is always a tedious 
and delicate operation, and a discussion of the various methods proposed 
would fill a volume. With the simple statement that the acid is finally 
weighed as uranium or magnesium phosphate, the reader is referred to 
the works on analytical chemistry. 



COMPOUNDS OF PHOSPHOKUS AND SULPHUR. 115 



Action on the Economy. 

Although the salts of orthophosphoric acid are important constituents 
of animal tissues, and give rise, when taken internally in reasonable doses, 
to no untoward symptoms; and although the acid itself, when ingested, 
may act deleteriously purely by virtue of its acid reaction, the recent re- 
searches of Gamgee, Priestley, and Larmuth, have shown that meta- and 
pyrophosphoric acids, even when taken in the form of neutral salts, have 
a distinct action (the pyro being the more active) upon the motor ganglia 
of the heart, producing diminution of the blood-pressure, and, in compara- 
tively small doses, death from cessation of the heart's action. The dis- 
tinction between the glacial and dilute acids of the United States Phar- 
macopoeia becomes of importance in view of these facts. 



Compounds of Phosphorus with Elements of the Chlorine Group. 

The compounds of phosphorus and chlorine are three in number: 
PC1„ PC1 5 , and POCl 3 . 

Phosphorus trichloride — PC1 3 — is prepared by passing vapor of phos- 
phorus over mercuric chloride; or, preferably, by passing a slow current 
of dry chlorine over phosphorus, and purifying by distillation. 

It is a colorless liquid; sp. gr. 1.61; has an irritating odor; fumes in 
the air; boils at 76°. On contact with water it is decomposed, with for- 
mation of phosphorous and hydrochloric acids. It is a very valuable 
reagent in organic chemistry. 

Phosphorus pentachloride — PC1 5 — is formed by the action of an ex- 
cess of chlorine upon phosphorus, or upon the trichloride. 

It occurs in light yellow crystals, having a powerful odor, giving off 
irritating vapors, and distilling at about 145°. At higher temperatures 
it is decomposed into PC1 3 + C1 2 . With a small quantity of water it 
forms the oxychloride, POCl 3 , and hydrochloric acid; with a large quan- 
tity, phosphoric and hydrochloric acids. Is useful as a reagent in organic 
chemistry. 

Phosphorus oxychloride — POCl 3 — is formed by the action of a limited 
quantity of water on the pentachloride. It is a colorless liquid; sp. gr. 
1.7; boils at 110°; solidifies at — 10°; and has a pungent odor. Use; the 
same as that of the other chlorides. 

With bromine, phosphorus forms compounds similar in composition 
and properties to the chlorine compounds. 

With iodine, it forms two compounds, PI 2 and PI 3 , both solid, crystal- 
line bodies, obtained by the direct union of their elements, and both de- 
composed, on contact with water, into hydriodic and phosphorous acids. 

Two fluorides of phosphorus, PF 3 and PF 5 , are also known — the former 
liquid, the second gaseous. 



Compounds of Phosphorus and Sulphur. 

No less than six compounds of these elements have been described, 
having the formulae : P 4 S, P 2 S, P 4 S 3 , P 2 S 3 , P 2 S 5 , P 2 S 12 . Two of these, P 2 S 3 
and P 2 S 5 , correspond to the oxides. Although of great interest in con- 
nection with theoretical chemistry, they are not of medical interest. 



116 GENERAL MEDICAL CHEMISTRY. 

ARSENIC. 
Arsenicum As 75 

Compounds of arsenic, notably the sulphides, were known to the an- 
cients, and the element itself to the alchemists as early as the fourth cen- 
tury, when Geber makes mention of it. 

Arsenic occurs in nature in the form of metallic arsenides, but princi- 
pally as the sulphides, orpiment and realgar, and in arsenical iron pyrites, 
or mispickel, the last-named mineral being one of the chief sources from 
which it and its compounds are industrially obtained. It is also found in 
the elementary form in small quantities, and distributed in a vast number 
of other substances in quantities which, if not large, are sufficiently so to 
become a serious inconvenience to the toxicologist. 

It is obtained for use in the arts, either by calcining mispickel and 
condensing the volatilized arsenic in iron tubes, or by heating a mixture 
of arsenious oxide and charcoal, when the former is reduced and element- 
ary arsenic distils over. 

It is a brittle, light steel-gray solid, having a metallic lustre; sp. gr. 
5.75. When heated under the ordinary pressure, and without contact 
with air, it volatilizes without previous fusion. Under strong pressure it 
liquefies at a red heat. The density of its vapor is 10. 2A — 147.3H at 
560°; 10. 6A — 153H at 860°. Its vapor is yellowish, and has the odor of 
garlic, which is probably developed during oxidation. It is insoluble in 
water and in other liquids which do not act upon it chemically (see p. 125). 

When heated in air, arsenic is rapidly oxidized to arsenic trioxide, 
and ignites at somewhat below a red heat. In oxygen it burns with a 
brilliant white light, having a bluish tinge. In dry air it is not altered, 
but when exposed to damp air its surface rapidly becomes tarnished by 
oxidation. Its oxidation is attended by the development of an alliace- 
ous odor. In water it is slowly oxidized, a portion of the oxide formed 
dissolving in the water. It unites readily with chlorine, bromine, iodine, 
sulphur, and most of the metals. With hydrogen it only combines when 
that element is in the nascent state. Sulphuric acid, when warm and 
concentrated, is decomposed by arsenic with formation of sulphur di- 
oxide, arsenic trioxide, and water. Nitric acid is readily decomposed, 
giving up its oxygen to the formation of arsenic acid. 

With hydrochloric acid, aided by heat, arsenic trichloride is formed. 
Arsenic is oxidized by fusion with potassium hydrate, hydrogen is given 
off, and a mixture of arsenite and arsenide of potassium remains, which, 
by increase of temperature, is converted into arsenic and potassium 
arsenate, the former of which volatilizes, and the latter remains. 

Arsenic is used in the arts to some extent in pyrotechny, entering 
into the composition of the Bengal light (which should, therefor, only be 
used in the open air), in the manufacture of shot, and of fly-poison, and 
as a medicine in veterinary practice. It is poisonous (see p. 125). 

Compounds of Arsenic -with Hydrogen. 

Two of these are known, one gaseous, the other solid. 

Hydrogen arsenide, arseniuretted hydrogen, arsenia, arsenamine, AsH 3 
— a compound whose composition is similar to that of ammonia and the 
corresponding phosphorus compound, and one which is of great practical 



COMPOUNDS OF ARSENIC WITH HYDROGEN. 117 

as well as theoretical interest. It does not exist in nature, and was dis- 
covered by Scheele. 

It is formed: First. — By the action of water upon an alloy, obtained 
by fusing together a mixture of two parts of natural sulphide of anti- 
mony, two parts of cream of tartar, and one part of arsenic trioxide. 

Seco7id. — By the decomposition of the arsenides of zinc and tin (as 
well as of other arsenides) by dilute hydrochloric or sulphuric acid. 

Third.— Whenever a reducible compound of arsenic is in the pres- 
ence of nascent hydrogen: 

As 2 O 3 + 0SO 4 H 2 + 6Zn=6SO 4 Zn + 3H 2 O+2AsH 3 . 

This reaction is utilized in Marsh's test (see p. 129). 

Fourth. — By the action of water upon the arsenides of the alkaline 
metals: 

AsNa 3 + 3H 2 = 3NaH0 + AsH 3 . 

Fifth. — By the combined action of moisture, air, and organic matter 
upon arsenical pigments (see p. 125). It is a colorless gas, having a 
strong alliaceous odor, soluble in five volumes of water free from air. 
Condenses to a mobile fluid at — 40°, does not solidify at — 110°; sp. gr. 
2.695A— 38.916H. 

It is not liable to spontaneous decomposition, but, in contact with air 
or oxygen, and moisture, its hydrogen is slowly removed by oxidation, 
.and elementary arsenic is deposited. It is also decomposed into its 
elements by the passage through it of the luminous electric discharge. 
A mixture of dry oxygen and hydrogen arsenide remains such under 
ordinary circumstances, but, upon heating it, it explodes with formation 
of arsenic trioxide and water, three volumes of oxygen oxidizing two of 
the arsenical gas: 

2AsH 3 + 30 2 =As 2 3 + 3H 2 0. 

With a quantity of oxygen less than that indicated in the equation, 
elementary, arsenic is deposited. 

If the gas be ignited as it issues from a jet, it burns with a greenish 
flame, from which rises a white cloud of arsenic trioxide ; if, however, the 
flame be cooled by the introduction of a cold body, the hydrogen is alone 
oxidized, the arsenic being deposited on the cold surface in its elementary 
form. If the gas be heated to redness as it passes through a glass tube, 
it is decomposed in whole or in part, hydrogen passing on and the arsenic 
being deposited. If hydrogen arsenide be caused to bubble through a 
solution of silver nitrate, that salt is decomposed ; elementary silver sepa- 
rates as a black powder, and the solution contains arsenic trioxide. The 
last three reactions are utilized in Marsh's test (q. v.). 

Chlorine decomposes the gas with great energy — the action, which is 
attended with considerable danger to the operator, being accompanied by 
an explosion, and the formation of hydrochloric acid and arsenic tri- 
chloride. Bromine and iodine act in a similar manner, but less violently. 

If hydrogen arsenide be passed over solid potassium hydrate, it is 
partially decomposed, the potash being coated with a blackish deposit of 
what would seem to be elementary arsenic. 

All oxidizing agents decompose the gas readily, water and arsenic 



118 GENERAL MEDICAL CHEMISTRY. 

trioxide being formed by the action of the less active oxidants, and water 
and arsenic acid by that of the more active. 

The alkaline hydrates absorb the gas, hydrogen is given off, and 
potassium arsenite remains in solution. Many metallic elements, when 
heated in an atmosphere of hydrogen arsenide, decompose it with forma- 
tion of a metallic arsenide, and liberation of hydrogen. 

Although hydrogen arsenide and hydrogen sulphide decompose each 
other to a great extent, with separation of arsenic trisulphide, the re- 
searches of Kubel, Meyers, and Otto have shown that the former gas is 
capable of existing, to some extent at least, in the presence of the latter; 
a fact which renders it necessary to use the greatest caution, in obtaining 
hydrogen sulphide for toxicological purposes, to use materials free from 
arsenic. 

Arseniuretted hydrogen is exceeding poisonous (see p. 125). 

Solid hydrogen arsenide. — The probable composition of this body is- 
As 2 H. It is a red-brown powder, insoluble in water and in alcohol. The 
only interest attaching to it is in connection with Marsh's test, in which 
care should be had to avoid the conditions under which it is formed. This 
may be done by carefully preventing the presence of any nitrate, and by 
moistening the zinc with a dilute solution of platinum chloride, which 
should be removed, and the zinc washed with pure water before the appa- 
ratus is mounted (see p. 129). 



Compounds of Arsenic and Oxygen. 

Only two of these are known with certainty : they are the trioxide,, 
As 2 3 , and the pentoxide, As 2 5 , corresponding to the similar phos- 
phorus compounds. It is probable that the gray substance, formed by 
the action of moist air and of water upon elementary arsenic, is a lower 
oxide than either of the above, possibly As 2 0. 



Arsenic Trioxide. 

Arsenious anhydride — "White arsenic — Arsenic — Arsenious acid — Aci- 
du?n arseniosum (U. S., Br.) — As 2 3 . — This substance does not exist in 
nature, but is manufactured in large quantities industrially, either as a dis- 
tinct product, by roasting mispickel, or as an incidental product in working 
the ores of cobalt and nickel. In either case the vapors are conducted 
into suitable condensing-chambers, where the solid trioxide is deposited 
as a white, crystalline powder, known in the arts &s flour of arsenic. From 
time to time this is removed (an operation attended with no little danger 
to the workman employed), and purified by a second sublimation. It 
sometimes occurs in this last process that, owing to the presence of ele- 
mentary arsenic, the iron pot in which the impure white arsenic is heated 
is perforated, and the contents, flowing into the fire, are volatilized into 
the air of the workshop, with fatal results. 

Arsenic trioxide is capable of existing, and occurs in commerce, in 
two distinct allotropic conditions : crystallized or u %>owdered" and vitre- 
ous. When freshly resublimed, it appears in colorless or faintly yellow, 
transparent, vitreous masses, having no visible crystalline structure. 
Shortly, however, these masses become opaque upon the surface, and 
present the appearance of porcelain ; this change, which is due to the 



AKSENIC TRIOXIDE, 



119 



substance assuming the crystalline form, gradually and slowly progresses 
toward the centre of the mass, which, however, remains vitreous for a 
long time. The change is attended by the slow liberation of heat, and, if 
it be made to take place more rapidly, a faint light is visible in obscurity. 
Whenever arsenic trioxide is sublimed, if the vapors be condensed upon 
a cool surface, it is deposited in the form of brilliant octahedral crystals, 
which are larger" and more perfect the nearer the temperature of the 
condensing surface is to 180°. The crystalline variety may be converted 
into the vitreous by keeping it for some time at a temperature near its 
point of volatilization. 

. The taste of arsenic trioxide is at first faintly sweet, afterward acrid, 
metallic, and nauseating. It is odorless; in aqueous solution (see below) 
it has a faintly acid reaction. The specific gravity of the vitreous variety 
is 3.689; that of the crystalline, 3.785. 

The solubility of this substance in water and in other fluids has been 
the subject of many investigations. In pure water, arsenic trioxide dis- 
solves as arsenious acid (q. v.); the amount dissolved depends upon the 
temperature, the method of making the solution, and the nature of the 
oxide. Thus, Bussy found that water at 13° is capable of dissolving forty 
grams of the vitreous oxide, but only twelve to thirteen grams of the 
crystalline to the litre; he found % also that, by prolonged boiling with 
water, the crystalline variety is converted into the vitreous, or, at all 
events, the solubility of the two varieties becomes the same — one hundred 
and ten grams to the litre of boiling water. According to Taylor, cold 
water dissolves from one to two grams per litre only; boiling water, when 
poured upon the oxide and allowed to cool, dissolves 2.5 parts in one 
thousand; and water boiled upon the oxide, twenty-five parts per one 
thousand. These results are probably too low, although those for cold 
water agree well with the figures given by Woodman and Tidy, which 
represent the latest experiments upon the subject, and are given below: 





Transparent form. 


Opaque form. 


Fresh crystalline 
oxide. 


1,000 parts of cold distilled water, after 
standing 24 hours, dissolved 

1,000 parts of boiling water poured on 
the oxide, and allowed to stand for 
24 hours, dissolved 


1.74 parts. 
10.12 parts. 

64.5 parts. 


1 . 16 parts. 
5 . 4 parts. 

76.5 parts. 


2.0 parts. 
15 . parts. 


1,000 parts of water boiled for one hour, 
the quantity being kept uniform by 
the addition of boiling water from 
time to time, and filtered immedi- 


87.0 parts. 





These results for boiling water agree better with those of Bussy than 
with those of Taylor. 

The solution of the crystallized oxide in cold water is always very 
slow (the vitreous oxide dissolves more rapidly), and continues for a long 
time. If white arsenic be thrown upon cold water, only a portion of it 
sinks, the remainder floating upon the surface, notwithstanding its high 
specific gravity. This is due to a repulsion of the water from the sur- 
faces of the crystals, which also accounts, to some extent at least, for its 
slow solution. Even after several days cold water does not dissolve all 



120 GENERAL MEDICAL CHEMISTRY. 

the oxide with which it is in contact. Gmelin has shown that if one part 
of oxide be digested w 7 ith eighty parts of water, at ordinary temperatures 
for several days, the resulting solution contains -fa ; with 1G0 parts water, 
•j^Po ; with 240 parts, ■^s'o '■> with 1,000 parts water, -j-gVo 5 an ^ that, even 
when 16,000 or 100,000 parts of water are used, a portion of the oxide re- 
mains undissolved. The same author has shown that arsenious oxide, 
which has remained in contact with cold water in closed vessels for eigh- 
teen years, dissolves to the extent of 1 part in 54 of water, or 18.5 parts 
in 1,000, which may be given as the maximum solubility of the crystal- 
lized oxide in cold water. 

The power of water of holding the acid in solution, once it is dissolved, 
is not the same as its power of dissolving it. If a concentrated solution 
be made by boiling water upon the oxide and filtering hot, the filtrate may 
be evaporated down to one-half its original bulk without depositing any 
of the acid, of which this concentrated fluid now contains as much as one 
part in six of water, or 16G.6 parts per 1,000. If a hot solution of the 
acid be allowed to cool, the solution will contain 62.5 parts per 1,000 at 
16°, and 50 parts per 1,000 at 7°. 

The solubility of the oxide in alcohol varies with the strength of the 
spirit and the nature of the oxide, the vitreous variety being more soluble 
in strong than in weak alcohol, while the contrary is the case with the 
crystalline, as is shown in the following table: 

Alcohol at Alcohol at Alcohol at Absolute 



1.000 parts dissolve K « u , ™ I ^ UUUUi ™ 

1 56 per cent. 79 per cent. Sb per cent. 



alcohol. 



I 



At 15° 16.80 14.30 7.15 0.25 

Crystallized oxide -^ Attheboiling- 

( point 48.95 45.51 31.97 34.02 

Vitreous oxide at 15° 5.04 5.40 10.60 

The presence of the mineral acids and alkalies, ammonia and ammoni- 
acal salts, alkaline carbonates, tartaric acid, and the tartrates, increases 
the solubility of arsenic trioxide in water. 

A solution of the acid in dilute hydrochloric acid is officinal — Liquor ar- 
senici kyclrochloriciis (U. S., Br.), and, when made according to the direc- 
tions of the Pharmacopoeia, does not contain arsenic trichloride, but is sim- 
ply a solution of arsenious acid in diluted hydrochloric acid. 

Arsenic trioxide is less soluble in fluids containing fats or extractive 
or other organic matters (the various liquid articles of food), than it is in 
pure water. 

In chemico-legal cases, in which the question of the solubility of arsenic 
is very likely to arise, it must not be forgotten that the quantity of arsenic 
trioxide which a person may unconsciously take in a given quantity of 
fluid is not limited, under certain circumstances, to that which the fluid is 
capable of dissolving y a much greater quantity than this may be taken 
while in suspension in the liquid, especially if it be mucilaginous. 

Arsenic trioxide is readily decomposed by reducing agents, elementary 
arsenic being deposited, a decomposition which occurs when it is heated 
with hydrogen, carbon, potassium cyanide, etc. ; and at a lower tempera- 
ture by more active reducing agents. Oxydizing agents, on the other 
hand, such as nitric acid, the hydrates of chlorine, chromic acid, etc., con- 
vert it into arsenic pentoxide, or arsenic acid. 

Its solution, acidulated with hydrochloric acid, is decomposed when 
boiled with metallic copper, and an alloy of copper and arsenic is de- 



AKSENIC ACIDS. 121 

posited as a gray film upon the copper (see p. 127). Arsenic trioxide is 
largely used in the arts, in the manufacture of glass, green pigments, 
and vermin-poisons; in the processes of dyeing, in the preservation of 
anatomical preparations, and by the taxidermist. It is one of the com- 
monest of poisons (see p. 125). 



Arsenic Pentoxide. 

Arsenic anhydride — As 2 5 — is obtained by heating arsenic acid to 
redness. It is a white, amorphous solid, which, when exposed to the air, 
slowly absorbs moisture. It is fusible at a dull red heat, and at a slightly 
higher temperature decomposes to arsenic trioxide and oxygen. It 
dissolves slowly in water, forming arsenic acid, As0 4 H 3 . 



Arsenic Acids. 

These substances form a series, resembling the corresponding com- 
pounds of phosphorus. No arsenic compound corresponding to hypo- 
phosphorous acid has, however, been discovered as yet: 

Arsenious acid As0 3 H 3 . 

Arsenic acid As0 4 H 3 . 

Pyroarsenic acid As 2 7 H 4 . 

Metarsenic acid AsO s H. 

Arsenious acid, As0 3 H 3 . — Although this acid has not been sepa- 
rated, its existence in solutions of the trioxide may be presumed, espe- 
cially as the solution has a faintly acid reaction. Its composition is similar 
to that of phosphorous acid, and, as is the case with that acid, two only 
of the atoms of hydrogen are replaceable. Corresponding to this acid 
are a number of important salts, called arsenites, which have the general 
composition As0 3 HM' 2 , As0 3 HM", (As0 3 ) 2 H 4 M". 

Arsenites have also been obtained which seem to correspond to a 
pyroarsenious acid, As 2 5 H 4 , and others corresponding to a metarsenious 
acid, As0 2 H. 

Arsenic acid — Orthoarsenic acid — As0 4 H 3 — is obtained by oxidizing 
arsenic trioxide with nitric acid, in the presence of water: 

As 2 3 + 2H 2 + 2N0 3 H =2 As0 4 H 3 + N 2 3 . 

The oxidation may also be brought about by chlorine, aqua regia, or 
other oxidizing agents. A syrupy solution is thus obtained which, at 
15° or below, becomes semi-solid from the formation of transparent crys- 
tals, containing one molecule of water of crystallization. These crystals, 
which are very deliquescent and closely resemble in appearance those of 
sodium sulphate, lose their water of crystallization when heated to 100°, 
and form a white, pasty mass composed of minute crystalline needles, 
which are anhydrous. 

Arsenic acid is very soluble in water, the solution being strongly acid 
in taste and in reaction; colorless and odorless. 

In the presence of nascent hydrogen, arsenic acid is decomposed with 
formation of water and hydrogen arsenide. It is readily converted into 



122 GENERAL MEDICAL CHEMISTRY. 

the lower stage of oxidation of arsenic by the action of reducing agents. 
A current of sulphur dioxide passed through its solution converts it into 
arsenious acid. If hydrogen sulphide be passed through a solution of 
arsenic acid or of an arsenate, the first portions of the gas reduce the 
arsenical compound to arsenious acid, while sulphur separates. After 
this action has occurred, the arsenious acid is itself decomposed, with 
formation of arsenic trisulphide. 

Hydrochloric acid, even when concentrated and boiling, forms with 
arsenic acid mere traces of arsenic trichloride. 

Like phosphoric acid, arsenic acid is tribasic; and the arsenates re- 
semble the phosphates in composition, and in many of their chemical and 
physical properties. 

Although not as poisonous as arsenious acid (Woehler and Frerichs) 
in solutio?is of equal strength, it is quite as dangerous a substance, owing 
to its greater solubility. It is manufactured in large quantities industri- 
ally, and is used in dj^eing and in the manufacture of fuchsine (q. v.). 

Pyroarsenic acid, As 2 7 H 4 . — The resemblance between the phos- 
phorus acids and those of arsenic is visible in the action of heat upon 
arsenic acid, as well as in other properties. If arsenic acid be heated to 
140°-180°, there form compact masses of hard crystals having the above 
composition, and formed, like pyrophosphoric acid, by the union of two 
molecules of the orthoacid with separation of the elements of one mole- 
cule of water. This acid is quite unstable and readily takes up the ele- 
ments of water again, with regeneration of orthoarsenic acid; for this 
reason it is not soluble in water without decomposition. It forms salts 
having the same constitution as the pyrophosphates. 

Metarsenic acid, As0 3 H. — If pyroarsenic (or arsenic) acid be main- 
tained at a temperature of 200°— 206° for some time, a further loss of 
water occurs, and an acid is formed having the composition As0 3 H, the 
transformation taking place rather suddenly. It appears in the form of 
white, pearly crystals, which dissolve readily in water, the act of solution 
being attended with a considerable elevation of temperature and the re- 
generation of arsenic acid. It is a monobasic acid. 



Compounds of Arsenic and Sulphur. 

Quite a number of compounds of these elements have been described, 
some of which are more probably mixtures than definite compounds. 
Three, however, are well characterized: 

Arsenic disulphide As 2 S 2 . 

Arsenic trisulphide As 2 S 3 . 

Arsenic pentasulphide As 2 S 5 . 

Arsenic disidphide — Red sulphide of arsenic — Realgar — Red orpiment 
— Ruby sidphur — Red sidphuret of arsenic — Sandarach — As 2 S 2 . — Exists 
in nature in the form of translucent, ruby-red crystals. It is also prepared 
artificially by fusing together seventy-five parts of arsenic and thirty-two 
parts of sulphur, or by heating a mixture of sulphur and arsenic trioxide; as 
so prepared it appears in brick- or ruby-red fragments, having a conchoidal 
fracture. It is fusible, insoluble in water, but soluble in solutions of the 
alkaline sulphides and in a boiling solution of potassium hydrate. It is 
used in the arts, in pyrotechny, and as a pigment. 



COMPOUNDS OF ARSENIC. 123 

Arsenic trisulphide — Orpiment — Auripigmentum — Yellow sulphide or 
Sulphuret of arsenic — King^s yellow — As 2 S 3 . — Occurs in nature in bril- 
liant, golden yellow flakes. Obtained artificially by passing hydrogen sul- 
phide through a solution of arsenious acid, or by heating a mixture of 
arsenic and sulphur, or of arsenic trioxide and sulphur. 

It is a lemon-yellow powder when obtained by precipitation, and in 
orange-yellow crystalline masses when prepared by sublimation. 

It is almost insoluble in cold water, but sufficiently soluble in hot water 
to communicate to it a distinctly yellow color. By continued boiling with 
water it is decomposed, with formation of hydrogen sulphide and arse- 
nious acid. The limited solution of this substance in water does not take 
place in the presence of a small quantity of hydrogen sulphide. It is in- 
soluble in dilute hydrochloric acid, but very soluble in solutions of the al- 
kaline hydrates, especially in solution of ammonium hydrate, and in so- 
lutions of the alkaline carbonates and sulphides. 

Nitric acid oxidizes it quickly, forming arsenic and sulphuric acids. 
The same decomposition occurs with nitrohydrochloric acid, and with 
hydrochloric acid and potassium chlorate. 

Arsenic trisulphide corresponds in constitution to. the trioxide, atoms 
of sulphur taking the place of those of oxygen. Like that body, it may 
be regarded as an anhydride, although it contains no oxygen; for, not- 
withstanding the fact that sulpharsenious acid, AsS 3 H 3 , has not been sepa- 
rated, its existence must be regarded as possible from that of the well- 
characterized sulpharsenites, pyrosulpharsenites, and metasulpharsenites,. 
similar in constitution to the salts of the corresponding oxygen acids. 

Orpiment is used in the arts as a pigment, under the name of King^s 
yellow, and, as such, has given rise to many cases of so called " accidental " 
poisoning, by being mistaken for more harmless coloring matters and 
introduced into articles of food with more or less innocent intent. Al- 
though the natural product is probably inert, the artificial is actively 
poisonous, from the presence in it of arsenic trioxide. In cases of death 
from arsenical poisoning, the arsenic is liable to be converted into the 
trisulphide, after long burial. 

Arsenic pentasulphide, As 2 S 5 — is said to have been obtained by 
fusing a mixture of the trisulphide and sulphur in proper proportions, 
as a yellow, fusible solid, capable of sublimation in the absence of air. 
The precipitate which is formed when a solution of an arsenate is 
treated with hydrogen sulphide is not this substance, but a mixture of the 
trisulphide and sulphur. Whether or no this body exists in the free state 
(and its existence has been called in question), there exist well-defined 
salts, sulpharsenates, pyrosulpharsenates, and metasulpharsenates, to 
which this body bears the same relation that arsenic pentoxide does to 
the corresponding oxygen compounds. 



Compounds of Arsenic with the Elements of the Chlorine 

Group. 

Arsenic trifluoride, AsF 3 — a colorless, fuming liquid, boiling at 63° r 
capable of attacking glass, obtained by distilling a mixture of arsenic 
trioxide, fluorspar, and sulphuric acid. 

Arsenic trichloride, AsCl 3 . — Obtained by distilling a mixture of 
arsenic trichloride, sulphuric acid, and sodium chloride, using a well- 
cooled receiver. 



124 GENERAL MEDICAL CHEMISTRY. 

It is a colorless liquid, boils at 134°, fumes when exposed to the air, 
and volatilizes readily at temperatures below its boiling-point. Its for- 
mation must be avoided in processes for the chemico-legal detection of 
arsenic, lest it be volatilized and lost. 

It is formed by the action of hydrochloric acid, even when compara- 
tively dilute, upon arsenic trioxide at the temperature of the water-bath ; 
but, if potassium chlorate be added, the trioxide is oxidized to arsenic 
acid, and the formation of the chloride thus prevented. Arsenic trioxide, 
when fused with sodium nitrate, is converted into sodium arsenate, which 
is not volatile ; if, however, small quantities of chlorides be present, 
arsenic trichloride is formed (see p. 129). It is highly poisonous. 

Arsenic tribromlde, AsBr 3 . — Obtained by adding powdered arsenic 
to bromine, and distilling the product at 220°. A solid, colorless, crys- 
talline body, fuses at 20°— 25°, boils at 220°, and is decomposed on con- 
tact with water. 

Arsenic triiodide. AsL. — Obtained by adding arsenic to a solution of 
iodine in carbon disulphide, or by fusing together arsenic and iodine in 
proper proportions. A brick-red solid, fusible and capable of volatilizing 
unchanged. In a large quantity of water it dissolves ; with a small 
quantity it is decomposed, with formation of hydriodic acid, arsenic tri- 
oxide, water, and a residue of arsenic triiodide. 

Arsenic triiodide, prepared by fusion, is officinal as Arsenici iodidum, 
(U. S.), and enters into the composition of the Liq. arsenici et hydrargyri 
iodidi (U. S.), or Donovan's solution. 



Action of Arsenical Compounds upon the Animal Economy. 

The poisonous nature of many of the arsenical compounds has been 
known from a remote period, and it is probable that more murders have 
been committed by their use than by that of all other toxic substances 
combined. Even at the present time — notwithstanding the fact that, sus- 
picion once aroused, the detection of arsenic in the dead body is certain 
and comparatively easy — criminal arsenical poisoning is still quite com- 
mon, especially in rural districts. It would seem, however, that in France, 
phosphorus is more frequently used ; while in England, opium and its 
preparations are the favorite agents of the poisoner. 

Of poisons used by suicides in this Country, the arsenical compounds 
(especially Paris green, aceto-arsenite of copper) maintain their posi- 
tion at the head of the list. The great majority of cases of arsenical 
poisoning which come to our notice are suicidal ; we are forced, however, 
by statistics and experience, to believe that this proportion would be much 
reduced were it not that the secrecy enshrouding homicidal poisoning is 
only penetrated in a small percentage of cases — not from the fault of the 
chemist, but from that of physicians, coroners, and other prosecuting 
officers.* 

The poison usually enters the circulation by the alimentary canal, 
being taken by the mouth; but instances are not wanting in which it has 

* The last conviction of the crime of murder by poison in New York City was that 
of Stephens, in 1858. During the following period of nearly a quarter of a century, 
Paris and London have witnessed many trials of cases of homicidal poisoning, while 
New York would seem to be either free from the crime, or a safe place for those who 
desire to murder in this way. 



ACTION OF AKSENICAL COMPOUNDS. 125 

been introduced in other ways: by the skin, to which it has been applied 
in the form of ointment; by abraded surfaces, to which it has been ap- 
plied by quacks as a " cancer cure;" by the rectum, vagina, or male 
urethra. 

The substances taken or administered have been: 

First. — Elementary arsenic, usually in the shape of fly-poison, which, 
however, contains arsenic trioxide as well. Elementary arsenic is not 
poisonous so long as it remains such / in contact with water, or with the 
saliva, however, it is converted into an oxide, which is then dissolved, 
and, being capable of absorption, produces the characteristic effects of 
the arsenical compounds. 

Second. — Hydrogen arsenide, the most actively poisonous of the in- 
organic compounds of arsenic, has not been used by the homicide or the 
suicide. Several cases of accidental death from its effects have been 
recorded, prominent among which is that of the chemist Gehlen, who 
died in consequence of having inhaled a few bubbles of the gas while ex- 
perimenting upon it. In other cases death has followed the inhalation 
of hydrogen, made from zinc, or sulphuric acid contaminated with arsenic. 
Third. — Arsenic trioxide has been the substance administered in a- 
great number of cases of homicidal poisoning, has been used to a limited- 
extent by suicides, and has been frequently taken or administered by 
mistake or accident. It has been given by every channel of entrance to 
the circulation; in some instances concealed with great art, in others 
merely held in suspension by stirring in a transparent fluid given to an 
intoxicated person. If the poison have been given in quantity, and un- 
dissolved, it may be found in the stomach after death in the form of 
eight-sided crystals, more or less worn by the action of the solvents with 
which it has come in contact. 

The lethal dose is variable, death having occurred from two and one- 
half grains, and recovery having followed the taking of a dose of two- 
ounces. It is more active when taken fasting than when taken on a full, 
stomach, in which latter case all, or nearly all, the poison is frequently 
expelled by vomiting, before there has been time for the absorption of 
more than a small quantity. 

Fourth. — Potassium arsenite, the active substance in "Fowler's solu- 
tion," although largely used by the laity in malarial districts as an ague- 
cure, has, so far as the records show, produced but one case of fatal poi- 
soning. 

Fifth. — Sodium arsenite is sometimes used to clean metal vessels, a. 
practice whose natural results are exemplified in the death of an individual 
who drank beer from a pewter mug so cleaned; and in the serious illness* 
of three hundred and forty children in an English institution, in which 
this material had been used for cleaning* the water-boiler. 

Sixth — Arsenic acid and arsenates. — The acid itself has, so far as we 
know, been directly fatal to no one. The cases of death and illness, 
however, which have been put to the account of the red anilin dyes, are 
not due to them directly, but to arsenical residues remaining in them as 
the result of careless processes of manufacture. 

Seventh. — Sulphides of arsenic. — Poisoning by these is generally due 
to the use of orpiment, introduced into articles of food as a coloring mat- 
ter, by a combination of fraud and stupidity, in mistake for turmeric. 

Eighth. — Tlie arsenical greens. — Scheele's green or cupric arsenite,. 
and Schweinfurth green or cupric aceto-metarsenite (the latter com- 
monly known in the United States as Paris green, a name applied in* 



126 GENERAL MEDICAL CHEMISTRY. 

Europe to one of the anilin pigments). These substances, although 
rarely administered with murderous intent, have been the cause of death 
in a great number of cases. Among suicides in the lower orders of the 
population in large cities, Paris green has been the favorite. 

The arsenical pigments may also produce disastrous results by " acci- 
dent;" by being incorporated in ornamental pieces of confectionery; by 
being used in the dyeing of textile fabrics, from which they may be easily 
rubbed off; and by being used in the manufacture of wall-paper. Many 
instances of chronic or subacute arsenical poisoning have resulted from in- 
habiting rooms hung with paper whose whites, reds, or greens were pro- 
duced by arsenical pigments. From such paper the poison is disseminated 
in the atmosphere of the room in two ways: either as an impalpable 
powder, mechanically detached from the paper and floating in the air, or, 
as Fleck has shown, by their decomposition, and the consequent diffusion 
of volatile arsenical compounds in the air. 

The treatment in acute arsenical poisoning is the same, whatever may 
be the form in which the poison has been taken. The first indication is 
the removal of any unabsorbed poison from the alimentary canal. If 
vomiting have not occurred from the effects of the toxic, it should be in- 
duced by the administration of zinc sulphate, or by mechanical means. 
The stomach-pump should not be used unless the case is seen soon after 
the taking of the poison. When the stomach has been emptied, the 
chemical antidote is to be administered, with a view to the transforma- 
tion in the stomach of any remaining arsenical compound into the insolu- 
ble, and, therefor, innocuous ferrous arsenate. From recent experi- 
ences, it would seem that the preparation known as " dialyzed iron " is 
very efficacious; failing this, ferric hydrate must be prepared extempo- 
raneously, as when dry or not recently prepared it has no longer the power 
of combining with the arsenical compound. To prepare this substance a 
solution of ferric sulphate, Liq. ferri tersulphatis (U. S. ) = Liq. ferri 
persulphatis (Br.), is diluted with three volumes of water and treated with 
aqua ammonias in slight excess. The precipitate formed is collected upon 
a muslin filter and washed with water until the washings are nearly taste- 
less. The contents of the filter — Ferri oxidum hydration (U. S.), Ferri 
peroxidum humidum, (Br.) — are to be administered, while still moist, in 
frequently repeated doses of one or two teaspoonf uls until the faeces become 
black or very dark in color from the presence of ferrous sulphide. This 
treatment applies only to those cases in which the poison has been taken 
by the mouth, and has for its object the removal of those portions which 
are not yet absorbed. The symptoms caused by the absorbed poison are 
to be treated as they arise. 



Toxicol6gical Analysis. 

Precautions to be taken by the Physician. — It will rarely happen 
that in a case of suspected homicidal poisoning by arsenic, or by other 
poisons, the physician in charge will be willing or competent to conduct 
the chemical analysis upon which probably the conviction or acquittal of 
the accused will mainly depend. Upon his knowledge and care, however, 
the success or futility of the chemist's labors depend in a great measure. 

It is, as a rule, the physician who first suspects foul play; and, while it 
is undoubtedly his duty to avoid any public manifestation of his suspicion, 
it is just as certainly his duty toward his patient and toward the com- 



TOXICOLOGICAL ANALYSIS. 127 

munity to satisfy himself as to the truth or falsity of his suspicion by the 
application of a simple test to the excreta of the patient during life, the 
result of which may enable him to prevent a crime, or, failing that, take 
the first step toward the punishment of the criminal. 

In a case in which, from the symptoms, the physician suspects poison- 
ing by any substance, he should himself test the urine or fasces, or both, 
and govern his treatment and his actions toward the patient, and those 
surrounding the patient, by the results of his examination. Should the 
case terminate fatally, he should at once communicate his suspicions to 
the prosecuting officer, and require a post-mortem investigation, which 
should, if at all possible, be conducted in the presence of the chemist who 
is to conduct the analysis; for, be the physician as skilled as he may be, 
there are odors and appearances, observable in many cases at the opening 
of the body, full of meaning to the toxicological chemist, which are ephem- 
eral, and whose bearing upon the case is not readily recognized by those 
not thoroughly experienced. 

Cases frequently arise in which it is impossible to bring the chemist 
upon the ground in time for the autopsy; in such cases the physician should 
remember that that portion of the poison remaining in the alimentary 
tract (we are speaking of true poisons) is but the residue of the dose in 
excess of that which has been necessary to produce death; and, if the pro- 
cesses of elimination have been active, there may remain no trace of the 
poison in the alimentary canal, while it still may be detectable in deeper- 
seated organs. Moreover, the finding of poison in the stomach alone would 
not, at the present time, be sufficient to procure conviction of the crimi- 
nal, who might raise the very plausible question as to whether the poison 
was not injected by some malicious person into that viscus after death. 

For these reasons it is not sufficient to send the stomach alone for 
analysis; the chemist should also receive the entire intestinal canal, at 
least one-half the liver, the spleen, one or both kidneys, a piece of muscu- 
lar tissue, the brain, and any urine that may remain in the bladder. The 
intestinal canal should be removed and sent to the chemist without hav- 
ing been opened, and with ligatures enclosing the contents at the two ends 
of the stomach and at the lower end of the intestine. The brain and ali- 
mentary canal are to be placed in separate jars, and the other viscera in 
another jar together; the urine in a vial by itself. All of these vessels 
are to be new and clean, and are to be closed by new corks, or by glass 
stoppers, or covers (not zinc screw-caps), which are then coated with paraf- 
fine (not sealing-wax), and so fastened with strings and seals that it is im- 
possible to open the vessels without cutting the strings or breaking the 
seals. If the physician fail to observe these precautions, he has probably 
made the breach in the evidence through which the criminal will escape, 
and has at the outset defeated the aim of the analysis. 

Toxicological analysis. — Since the earlier days of toxicological chem- 
istry many processes for the detection of arsenic have been suggested, 
varying greatly as to the facility of their application and the reliability of 
the results obtained. 

Of these there is one which, although well adapted to the use of phy- 
sicians during the life of the patient, is of little value from a chemico- 
legal point of view ; we refer to Reinsch's test. 

The advantages of this method are that it may be applied to solutions 
containing organic matter, the urine for instance ; it is easily conducted, 
and its positive results are not misleading, if the test be carried to com- 
pletion. It is, therefor, the test which we should recommend physicians 



128 GENERAL MEDICAL CHEMISTRY. 

to apply to the urine, in cases which they suspect are due to arsenical 
poisoning ; but at the same time it is one whose application to any solid 
or fluid, after death, we should disapprove of strongly, unless complete evi- 
dence of the presence of the poison had already been obtained by the use 
of other tests. By its use copper is introduced into the substances ex- 
amined, which may seriously interfere with subsequent steps in the 
analysis, by rendering impossible a distinction between poisoning by 
arsenious anhydride and that by Paris green — a distinction which may 
become of vital importance if the defence claim the case to be one of 
suicide. Other disadvantages of Reinsch's test are that it is not as deli- 
cate as Marsh's test ; that by it arsenic in its higher state of oxidation is 
not detected ; the difficulty of obtaining copper free from arsenic ; and 
that its results are interfered with by the presence in the mixture tested 
of oxidizing agents. 

Reinsch's test consists in acidulating the suspected fluid (urine) with 
one-sixth its bulk of pure hydrochloric acid, immersing in the liquid a 
strip of pure electrotype copper, and boiling. If arsenic be present, a 
gray or bluish deposit will form upon the copper ; but, as such a deposit 
is produced by other substances (bismuth, antimony, mercury) as well as 
arsenic, the mere formation of this stain is not evidence of the presence 
of an arsenical compound. To complete the test the copper is removed, 
washed, and dried between folds of filter paper, without removing the de- 
posit. The copper, with its adhering deposit, is then rolled into a little 
cylinder, which is introduced into a piece of Bohemian tubing, about one- 
fourth of an inch in diameter and six inches long. The tube is then 
held at an angle of about 45 , the copper coil being about an inch and a 
half from the lower end, and heated at the point where the copper is. If 
the deposit be due to arsenic, a sublimate, consisting of octahedral crys- 
tals of arsenic trioxide, will form at some point in the upper, cool portion 
of the tube. 

Three precautions must be observed by the physician in using this 
test : 1. The freedom of the hydrochloric acid and copper from arsenic 
must be demonstrated by a blank testing. 2. No stain upon the copper 
is evidence of the presence of arsenic, unless it yield crystals of the tri- 
oxide as described. 3. It should never be used after the death of the 
patient, especially if there be any reason to believe that the case will be 
the subject of legal proceedings. 

In a case of supposed homicidal poisoning the analyst must not 
confine his attention to any one poison, however directly the circum- 
stances of the case may point to the use of this or that toxic. He must 
so conduct the analysis as to be enabled to predicate the absence or 
presence of each of the more usually employed poisons. For this reason 
a systematic course of analysis must be followed, in which the search for 
mineral poisons, phosphorus excepted, follows that of those of an organic 
nature. This arrangement is chosen, firstly, because the volatile and 
some of the alkaloidal poisons, being subject to decomposition in contact 
with putrefying organic material, must be sought for at the earliest pos- 
sible moment; and secondly, because, in searching for mineral poisons, it 
is necessary to destroy all organic matter, the presence of which would 
render the tests applied uncertain, and in many instances delusive. 

The best method of accomplishing this destruction of organic matter is 
that devised by Frezenius and von Babo. It consists in oxidizing the 
animal or vegetable substances by a mixture of hydrochloric acid and 
potassium chlorate. The material to be examined, divided into small 



TOXICOLOGIC AL ANALYSIS. 129 

pieces if solid, is rendered fluid by the addition of water, and, after the ad- 
dition of about 200 c.c. of hydrochloric acid, and four to five grams of potas- 
sium chlorate, is heated over the water-bath, small quantities of chlorate 
being added from time to time until the mass has a uniform light yellow 
color. If now it smell strongly of chlorine, it is warmed, and treated 
with a current of carbon dioxide until the chlorine odor has disappeared, 
when it is allowed to cool, is filtered, and the residue washed with hot 
water. The clear filtrate and washings, if strongly acid, are partially 
neutralized by the addition of sodium carbonate, and treated with a cur- 
rent of washed hydrogen sulphide, the gas being passed through the 
warmed liquid until, after shaking, it retains a strong odor of sulphur- 
etted hydrogen. The vessel is then corked and set aside until the fol- 
lowing day, when the same treatment is repeated, as again on a third day, 
a long contact with an excess of hydrogen sulphide effecting a more com- 
plete separati©n of the metallic sulphides than a treatment with a large 
volume of the gas during a shorter period. The precipitate formed is 
now collected upon a filter, and washed with water containing a small 
quantity of hydrogen sulphide, until the washings do not give the faint- 
est cloudiness when boiled, acidulated with nitric acid, and tested for 
chlorides by the addition of silver nitrate solution. 

The precipitate is then treated with solution of ammonium sulphy- 
drate, which effects a partial separation of the poisonous metals, some 
being dissolved and others remaining; arsenic trisulphide will pass into the 
solution. This is now evaporated over the water-bath to dryness, the 
residue moistened with strong nitric acid and again dried over the water- 
bath, the treatment with nitric acid being repeated two or three times. 
To the residue sodium carbonate and sodium nitrate are added, and the 
whole heated to fusion until colorless. It is then allowed to cool, and 
decomposed by the addition of strong sulphuric acid and gradual heating 
until all nitric acid is expelled, and until copious white fumes are given 
off. The residue is finally dissolved in water, and if there be any cloudi- 
ness in the solution (see p. 132), it is filtered and tested for arsenic by one 
of the following methods: 

Of all the tests hitherto devised for the detection of arsenic, the most 
delicate and the most certain is that originally suggested by James Marsh, 
in 1836, and subsequently so modified by Berzelius, Otto, and others, that 
but little of the original method remains beyond the principles upon 
which it is based (see p. 117). The apparatus consists of a gener- 
ating flask having a capacity of about 75 c.c, fitted with a cork through 
which pass a funnel-tube, drawn out and turned up at the lower end, and 
a tube bent to a right angle and carrying a bulb upon its horizontal 
limb. This tube communicates with a drying-tube, filled with fragments 
of calcium chloride enclosed between cotton plugs, and this in turn with 
a piece of Bohemian tubing, about an eighth of an inch in diameter and 
about two feet long, whose middle third is coiled in a spiral; finally, this 
Cube is connected with a right-angle tube, whose lower extremity dips 
into a solution of silver nitrate. 

To apply the test, the generating flask is charged with pure zinc, 
which is moistened with water containing a few drops of a solution of 
platinum chloride ; the solution is allowed to remain upon the zinc about 
ten minutes, and is then washed off. The apparatus is mounted in such a 
way that all its joints are gas-tight, and sulphuric acid, diluted with a 
little more than its bulk of water and cooled, is poured into the funnel- 
tube. After the generation of hydrogen has continued for about twenty 
9 



130 GENERAL MEDICAL CHEMISTRY. 

minutes, the coiled portion of the Bohemian tube is heated to redness, 
and the heating and evolution of hydrogen continued for a full half-hour. 
If at the end of this time the faintest deposit have formed in the cool por- 
tion of the tube, beyond the coil, the chemicals are to be rejected as im- 
pure, and the testing is to be repeated with others. If no deposit have 
formed, the suspected liquid, diluted if necessary with water, is slowly 
introduced through the funnel-tube in such a way that no air is carried 
down with it, that the generating flask does not become hot, and that the 
introduction of the entire quantity (which should not measure more than 
two or three fluid ounces) shall require from an hour to an hour and a 
half. If the proper precautions have been observed, and if the matters 
tested contained arsenic, a hair-brown or steel-gray deposit will have 
formed in the tube, beyond the coil. 

As Marsh's test is usually applied, this stain may be produced by anti- 
mony as well as by arsenic; but if the method indicated above have been 
followed, antimony, if present, will have been separated at an earlier stage 
of the process (see page 132). 

Some toxicologists direct that the final exit of the gas from a Marsh 
apparatus be from a drawn-out end of the tube, pointing upward, and 
that it shall be there ignited. If, under these conditions, the heating of 
the coil be discontinued, in the presence of arsenic a white, crystalline 
deposit of arsenic trioxide may be collected upon a glass surface held 
above the flame, or a brown or black deposit of elementary arsenic upon 
a cold, white, porcelain surface held in the flame. But this method — the 
original form of Marsh's test — is attended with a considerable loss of arsenic, 
and we therefor consider it preferable to collect any arsenic which may 
escape deposition in the tube in a solution of silver nitrate. The presence 
of arsenic in the silver solution may be subsequently detected by cautiously 
floating a small quantity of dilute ammonium hydrate solution upon the 
surface of the liquid, when a yellow cloudiness is observed at the line of 
contact. 

Owing to the difficulty formerly experienced in obtaining zinc free from 
arsenic, it was suggested that nascent hydrogen be obtained by the de- 
composition of acidulated water by the battery. This modification of the 
Marsh process is usually designated as Bloxam's test, as its use was 
recommended by that chemist in 1860 ; a similar apparatus was, however, 
suggested by Morton previous to 1847. 

If a determination of the quantity of arsenic present be required, the 
sulphuric acid solution obtained as directed on page 129 is not introduced 
directly into the Marsh apparatus, but is treated with sulphur dioxide, 
and then, after boiling until the excess of sulphur dioxide is driven off, 
with hydrogen sulphide. Any arsenic present is thus precipitated as the 
sulphide, in which form it is weighed, with the precautions indicated in 
the works on analytical chemistry. The estimation of arsenic as uranium 
or magnesium pyroarsenate, although excellent for technical purposes, 
is not available for the small quantities which the toxicologist has usually 
to deal with. The method by weighing the deposit formed in the Marsh 
test, recently suggested by Gautier, is not reliable. 

Another test is that suggested by Frezenius and von Babo. It con- 
sists in mixing the precipitate of sulphide, obtained as above, with a 
mixture of potassium cyanide and sodium carbonate, and heating in a 
tube through which passes a slow current of carbon dioxide. If arsenic 
be present it will appear in the cool part of the tube as a steel-gray deposit. 

To distinguish between an arsenite and an arsenate in solution, ad- 



ANTIMONY. 131 

vantage is taken of the colors of the two salts of silver. To the faintly 
acid solution to be tested, neutral solution of silver nitrate is added, and 
the mixture then rendered neutral by blowing upon it over the glass stop- 
per of a bottle moistened with ammonium hydrate solution. If an arsenite 
be present, the bright yellow silver arsenite is formed; and if an arsenate, 
the brick-red silver arsenate. 



ANTIMONY. 
Stibium Sb 122 

First described, about the middle of the fifteenth century, by Basil Val- 
entine. Occurs in nature, in its elementary form, in small quantity. Its 
chief ore, which was known to the ancients as crri/A/u, cttlJSl and stibium, is 
the trisulphide (q. v.). 

The element is obtained by roasting the sulphide, which is known in 
commerce as black antimony, or crude antimony, and reducing the oxide 
so obtained by heating it with charcoal. As the commercial product, 
known as regulus of antimony, is always contaminated with other sub- 
stances, notably with arsenic, it is necessary to purify it when it is to be 
used for medicinal or chemical purposes. This purification is effected by fus- 
ing a mixture of sixteen parts of commercial antimony, one part of the na- 
tive trisulphide of antimony, and two parts of dry sodium carbonate. After 
cooling, the antimony is removed, powdered, and again fused with one and 
one-half part of sodium carbonate and one per cent, of ferrous sulphide; 
finally, the antimony is again separated, powdered, and fused a third time 
with one part of sodium carbonate and a few fragments of sodium nitrate. 
Each fusion is maintained for an hour. 

Antimony is a bluish gray solid, having a brilliant metallic lustre, 
readily crystallizable by fusion and cooling; very brittle and easily pul- 
verized. Sp. gr. 6.715. It is tasteless and odorless, melts at 450°, vola- 
tilizes at a bright red heat, and may be distilled in an atmosphere of 
hydrogen. 

In its chemical properties and its compounds, antimony resembles ar- 
senic; it is not, however, as readily oxidized as that element, being unal- 
tered by exposure to air, dry or moist, at ordinary temperatures. When 
sufficiently heated in air it burns, with formation of the trioxide, as a 
white, crystalline sublimate, formerly known as argentine flowers of 
antimony. If melted antimony be dropped from a height, the small 
globules, exposing a large surface are rapidly oxidized, and in their 
passage through the air are followed by a white train of the trioxide. 
Antimony also unites directly with chlorine, bromine, iodine, sulphur, 
and with many metallic elements. Like arsenic, it unites indirectly with 
hydrogen. 

Cold, dilute sulphuric acid is without action on antimony; the hot 
concentrated acid converts it into antimonyl sulphate, while sulphur di- 
oxide is given off. When very finely divided, antimony is dissolved by 
hydrochloric acid under the influence of heat. Nitric acid oxidizes it 
readily with formation of antimonic acid, or of the intermediate oxide, - 
Sb 2 4 . It is readily dissolved by aqua regia, with which it forms either 
the trichloride, SbCl 3 , or the pentachloride, SbCl 6 . It is not dissolved by 
solutions of the alkaline hydrates. 



132 GENERAL MEDICAL CHEMISTRY. 

The element itself does not form salts with the oxacids. There are, 
however, compounds which are formed by the substitution of the group 
(SbO)', an univalent radical, for the basic hydrogen of those acids. Simi- 
lar compounds of vanadium and of arsenic are also known (see Tartar 
Emetic, p. 405). 

Antimony is also capable of uniting with many metals to form alloys, 
some of which are definite, crystalline compounds. 

Antimony is largely used in the arts, chiefly in the form of alloys, to 
which it communicates hardness and the property of expanding at the 
moment of solidification. Its principal use is as a constituent of type- 
metal; it also enters into the composition of "Britannia metal," " Queen's 
metal," and of the various anti-friction alloys used for the bearings of 
machinery. In a finely divided state it is applied to papier mache and 
plaster ornaments, to give them the appearance of steel. It is not used 
in medicine in its elementary form. 



Hydrogen Antimonide. 

Antimoniuretted hydrogen — Stibamine — Stibonia — SbH 3 . — Does 
not exist in nature, and has not as yet been obtained in a state of purity, 
being always mixed with a large quantity of hydrogen. Its composition, 
SbH 3 , corresponding to that of the hydrogen compounds of the other 
elements of this group, has been established beyond a doubt by the study 
of its products of substitution. 

It is a gaseous substance, formed from reducible compounds of anti- 
mony, under the same conditions which govern the formation of hydrogen 
arsenide. It is also subject to decompositions, similar to those of the 
arsenical compound. It differs from hydrogen arsenide in being by no 
means as poisonous, and in its action upon solutions of silver nitrate. 
Hydrogen arsenide, when passed through a solution of the silver salt, is 
decomposed according to the equation — 

6NO,Ag+AsH, + 3H/)=6N0 1 H + As0 1 H 8 +3Ag,, 

elementary silver being separated as a black powder, while arsenious 
acid remains in the solution, from which the yellow silver arsenite may 
be precipitated by cautiously floating dilute ammonium hydrate upon the 
surface of the clear liquid. 

In the case of hydrogen antimonide, a black deposit is also formed, but 
in this instance it is not elementary silver, but silver antimonide: 

3N0 3 Ag+SbH 3 =3N0 3 H+SbAg 3 . 



Distinction between Arsenic and Antimony by Marsh's Test. 

If the analysis have been conducted in the manner indicated upon 
p. 128, any antimony present is separated during the fusion with sodium 
nitrate and carbonate, and the subsequent solution and filtration, as an 
insoluble white powder, from which the element may be obtained by 
fusion with potassium cyanide, and its nature determined by solution in 



COMPOUNDS OF ANTIMONY AND OXYGEN. 



133 



aqua regia, which solution is then tested for antimony (see p. 138). If, 
however, Marsh's test be applied without the previous steps in the pro- 
cess, the stain of arsenic may be distinguished from that of antimony by 
the following differences: 



The Arsenical Stain. 

First. — Is farther removed from the 
heated portion of the tube, and, if small 
in quantity, is double — the first hair- 
brown, the second steel-gray. 

Second. — Volatilizes readily when heat- 
ed in an atmosphere of hydrogen, being 
deposited farther along in the tube ; the 
escaping gas has the odor of garlic. 

Third. — When cautiously heated in a 
current of oxygen, brilliant white octahe- 
dral crystals of arsenic trioxide are de- 
posited farther along in the tube. 

Fourth. —Instantly soluble in solution 
of sodium hypochlorite. 

Fifth. — Slowly dissolved by solution of 
ammonium sulphydrate; more rapidly 
when warmed. 

Sixth. — The solution obtained in 5° 
leaves, on evaporation over the water-bath, 
a bright yellow residue. 

Seventh. — The residue obtained in 6° 
is soluble in .-.qua ammoniae, but insoluble 
in hydrochloric acid. 

Eighth. — Is soluble in warm nitric acid ; 
the solution on evaporation yields a white 
residue, which turns brick-red when moist- 
ened with silver nitrate solution. 

Ninth. — Is nob dissolved by a solution 
of stannous chloride. 



The Antimonial Stain. 

First. — Is quite near the heated por- 
tion of the tube. 



Second. — Requires a much higher tem- 
perature for its volatilization ; fuses before 
volatilizing. Escaping gas has no alliace- 
ous odor. 

Third. — No crystals formed by heating 
in oxygen. 



Fourth. — Insoluble in solution of so- 
dium hypochlorite. 

Fifth. — Dissolves quickly in solution of 
ammonium sulphydrate. 

Sixth. — The solution obtained in 5° 
leaves, on evaporation over the water-bath, 
an orange-red residue. 

Seventh. — The residue obtained in 6° 
is insoluble in aqua ammoniae, but soluble 
in hydrochloric acid. 

Eighth. — Is soluble in warm nitric acid ; 
the solution on evaporation yields a white 
residue, which is not colored when moist- 
ened with silver nitrate solution. 

Ninth. — Dissolves slowly in solution of 
stannous chloride. 



"When, from the methods followed, it is doubtful whether the stain be 
antimonial or arsenical, it is well to use a number of small coils of heated 
tubing (see p. 129), through which the gas is made to pass in succession, 
rather than to attempt the collection of stains by the introduction of 
porcelain surfaces into the flame of the jet ignited as it issues from the 
end of the tube, as by the latter method of manipulation much of the 
antimony is lost. In conducting the Marsh test for antimony the pre- 
cautions mentioned on p. 130 are to be observed. 



Compounds of Antimony and Oxygen. 

Three compounds of these elements are known: 

Antimony trioxide Sb 2 3 . 

Antimony pentoxide Sb 2 5 . 

Intermediate oxide Sb 2 4 . 

Antimony trioxide — Antimonious anhydride— Oxide of antimony — 
timonii oxidum(U. S., Br.)— Sb s 8 — exists in nature, and is worked 



Antimonii 



134 GENERAL MEDICAL CHEMISTRY. 

as an ore of antimony in Algeria. It is,* however, generally prepared arti- 
ficially for use in the arts and medicine, by decomposing the oxychloride 
(q. v.). This decomposition may be effected in a variety of ways. The 
best method of obtaining the pure oxide consists in simply heating the 
oxychloride strongly in a crucible, when it is decomposed into trioxide and 
trichloride, the latter being volatilized. The United States Pharmacopoeia 
process consists in first obtaining the oxychloride, which is then decom- 
posed by dilute ammonium hydrate solution, and washing to separate 
the ammonium chloride formed. The British Pharmacopoeia process is 
similar, but the decomposition is effected by a solution of sodium car- 
bonate, instead of by ammonium hydrate. Antimony trioxide is also 
formed by heating antimony in a current of air, in the form of brilliant 
prismatic crystals, known formerly as Flores antimonii argentei, or Nix 
stibii. 

As prepared by the wet process, it is an amorphous, tasteless, and 
odorless powder, white at ordinary temperatures, but turning temporarily 
yellow when heated. It fuses readily, and, if protected from the oxygen 
of the air, volatilizes and condenses in the form of prismatic crystals. If 
strongly heated in contact with air, it burns like tinder, and is converted 
into the intermediate oxide, Sb o 0,. It is insoluble in water. 

7 2 4 

It is readily reduced, with separation of elementary antimony, when 
heated with carbon or in an atmosphere of hydrogen. It is also readily 
oxidized, as when brought in contact with nitric acid, or with solution of 
potassium permanganate. It dissolves in hydrochloric acid, with forma- 
tion of the trichloride; in Nordhausen sulphuric acid, from which solution 
there separate brilliant crystalline plates, having the composition S 2 7 
(SbO) 2 . It dissolves readily in solution of tartaric acid or of hydropotas- 
sic tartrate (see Tartar Emetic). By boiling solutions of the alkaline hy- 
drates it is gradually converted into antimonic acid. 

James' Powder, JPulvis antimonialis (Br.) is a mixture of antimony 
trioxide and tricalcic phosphate. 

Antimony pentoxide — Antimonic anhydride — Sb 2 6 — is obtained by 
heating metantimonic acid to dull redness. It is an amorphous, tasteless, 
and odorless solid, pale lemon-yellow when cool, and becoming tempora- 
rily darkened when heated. When heated to redness it gives off oxygen, 
and the intermediate oxide remains. It is very sparingly soluble in water 
and in acids. 

Intermediate oxide, Sb 2 4 — occurs in nature. It is formed when the 
oxides or hydrates of antimony are strongly heated, or when the lower 
stages of oxidation or the sulphides are oxidized by nitric acid, or by fu- 
sion with sodium nitrate. It is insoluble in water, but decomposed by 
hydrochloric acid, hydropotassic tartrate, and potash. 

The constitution of this compound is still undetermined. It is re- 
garded as the antimonic salt of metantimonic acid, Sb0 3 (SbO)', or as the 
anhydride corresponding to an acid having the composition Sb 2 6 H 2 . The 
latter view is probably the correct one, as by treatment with potash it 
yields a compound having the composition Sb 2 5 K 2 , which, by decompo- 
sition with an equivalent quantity of sulphuric acid, yields the acid 
Sb 2 5 H 2 . Moreover, there exists in nature a mineral (romeine) which is 
the calcium salt Sb 2 5 Ca. 



CHLOPwIDES OF ANTIMONY. 135 



Antimony Acids. 

The normal antimonous acid, Sb0 3 H 3 , corresponding to phosphorous 
acid, is not known; but the series of antimonic acids is complete, either 
in the form of salts or in that of the free acid: 

Orthoantimonic acid Sb0 4 H 3 . 

Pyroantimonic acid Sb 2 7 H 4 . 

Metantimonic acid Sb0 3 H. 

Besides these there also exists, in the shape of its sodium salt, a de- 
rivative of the lacking antimonous acid: 

Metantimonous acid Sb0 2 H. 

But little practical interest attaches to these acids, or to their salts. 
The compound sometimes used in medicine under the name loashed dia- 
phoretic antimony is potassium metantimonate, united with an excess of 
antimony pentoxide, 2Sb0 3 K, Sb 2 5 . 

The hydropotassic pyroantimonate, Sb 2 7 K„H 2 , 6Aq, is a valuable 
reagent for sodium, with which it forms the insoluble sodium salt. The 
reagent is obtained by calcining a mixture of one part of antimony with 
four parts of potassium nitrate, fusing the product with its own weight 
of potassium carbonate, and dissolving the resulting white mass in water 
as it is required for use. 



Chlorides of Antimony. 

Two chlorides and several oxychlorides are known: 

Antimony trichloride — Protochloride of antimony — Butter of anti- 
mony — SbCl a — is obtained by passing dry chlorine over an excess of an- 
timony or of antimony trisulphide, or by dissolving the trisulphide in 
hydrochloric acid, or by distilling together mixtures, either of antimony 
trisulphide and mercuric chloride, or of antimony and mercuric chloride, 
or of antimonyl pyrosulphate and sodium chloride. 

At low temperatures it is a solid, crystalline body; at the ordinary- 
temperature, a yellow, semi-solid mass, resembling butter; at 73.2° it melts 
to a yellow, oily liquid, which boils at 223°. 

When obtained by solution of the trisulphide in hydrochloric acid of 
the usual strength, it forms a solution with the water, which, concen- 
trated to sp. gr. 1.47, is the Liq. antimonii chloridi (U. S., Br.), used as 
an escharotic. 

The trichloride attracts moisture from the air and is soluble in a very 
small quantity of water. Upon the addition of a larger quantity of water, 
however, the chloride is decomposed, and a white powder is formed, 
which was formerly known as powder of algaroth, and which is now pre- 
pared as a step in the manufacture of the trioxide and of tartar emetic. 
The composition of this substance varies according as hot or cold water 
is used; if the latter, the decomposition is — 

SbCl 3 + H a O = 2HC1 + SbOCl ; 



136 GENERAL MEDICAL CHEMISTRY. 

but if the water be boiling — 

4SbCl 3 + 5H a O = 10HC1 + Sb 4 & Cl 3 . 

In water which contains at least fifteen per cent, of hydrochloric 
acid, antimony trichloride dissolves without the formation of a precipitate. 

Several cases of poisoning by butter of antimony, or by the Liq. 
antimonii chloridi, are upon record, the substance acting both locally 
as a corrosive and as a true poison. 

It is used in the bronzing of gun-barrels. 

Antimony pentachloride, SbCl 5 — is formed by the action of chlorine 
in excess upon antimony or antimony trichloride, and distillation in a 
current of chlorine. 

It is a fuming, colorless liquid, which solidifies at — 20°, but does not 
melt again until the temperature reaches — 6°. It absorbs moisture from 
the air. With a very small quantity of water, and by evaporation over 
sulphuric acid, it forms a hydrate having the composition SbCl 6 , 4H 2 0, 
which appears in the form of transparent, deliquescent crystals. With 
more water a crystalline oxychloride, SbOCl 3 , is formed; and with a still 
larger quantity, a white precipitate of orthoantimonic acid, Sb0 4 H 3 , is 
formed. It is capable of uniting with other chlorides to form double 
compounds, such as SbCl 5 , PC1 6 . 

With iodine, bromine, and fluorine, antimony forms compounds similar 
in composition to the trichloride. The triiodide, Sbl 3 , has been used in 
medicine. In its preparation the constituents must be brought together 
gradually to avoid explosions. 

Sulphides and Oxysulphides of Antimony. 

Two sulphides of antimony and a number of ill-defined oxysulphides 
are known. 

Antimony trisidphide — Slack antimony — Sulphur 'et of antimony — 
Antimonii sulphuretum (U. S.) SbS 3 . — Occurs in nature, and is the chief 
ore of antimony; it is also formed artificially when an excess of hydrogen 
sulphide is passed through a solution of tartar emetic. The native sul- 
phide is in the form of steel-gray, crystalline masses; the artificial pro- 
duct appears as an orange-red or brownish red, amorphous powder. It is 
met with in commerce, under the name " crude antimony," in conical 
loaves, obtained by simple fusion of the native sulphide to free it from 
gangue. 

It is soft, readily powdered, quite fusible, and has a brilliant metallic 
lustre. When heated in contact with air it is decomposed, sulphur 
dioxide is given off, and there remains a brown, vitreous, more or less 
transparent mass, composed of varying proportions of oxide and oxysul- 
phides, known as crocus, or liver, or glass of antimony. 

An oxysulphide of a fine red color, used as a pigment under the name 
antimony cinnabar or antimony vermilion, is obtained by the action, 
under the influence of heat, of a solution of sodium hyposulphite upon a 
solution of antimony trichloride, or of tartar emetic. It has the com- 
position Sb 6 S 6 3 . 

Antimony trisulphide is an anhydride, corresponding to which are 
salts known as sulphantimonites, having the general formula SbS a M' 2 H, 
If an excess of the trisulphide be boiled with a solution of hydrate of 



ANTIMONIAL ] POISONING. 137 

potassium, or of sodium, a solution is obtained containing an alkaline 
sulphantimonite and an excess of antimony trisulphide. If this solution 
be filtered and decomposed while still hot, an orange-yellow precipitate 
is obtained, which is the antimonium sulphiiretum (U. S., Br.), and con- 
sists of a mixture, in varying proportions, of the trisulphide and the tri- 
oxide. If, however, the solution be set aside and allowed to cool, a 
brown, voluminous, amorphous precipitate separates, which consists of 
antimony trisulphide, antimony trioxide, potassium or sodium sulphide, 
and alkaline sulphantimonite in varying proportions, and which is known 
as Kermes 1 mineral, antimonii oxy sulphur etum (U. S.). If now the solu- 
tion from which the kermes has separated, and which still contains an 
alkaline sulphantimonite, be decomposed with sulphuric acid, a reddish 
yellow substance, known as golden sulphuret of antimony, and which is a 
mixture of tri- and pentasulphides, separates. 

The precipitate obtained when hydrogen sulphide is passed through 
an acid solution of an antimonial compound is, according to circumstances, 
the trisulphide or the pentasulphide, mixed with varying quantities of 
free sulphur. 

By the action of hydrochloric acid upon the trisulphide, hydrogen 
sulphide is liberated; this method of obtaining that gas for toxicological 
analysis, formerly resorted to, is not to be recommended. In such anal- 
yses the use of red india-rubber tubing is to be avoided, as it owes its 
color to a sulphide of antimony. 

Antimony pentasulphide — Antimonic sulphide — Sb 2 S 5 — is obtained 
by decomposing an alkaline sulphantimonate by an acid. It is a dark 
orange-red, amorphous powder, readily soluble in solutions of the alkalies 
and alkaline sulphides, the solutions containing well-characterized salts, 
called sulphantimonates. One of these, sodium sulphantimonate, SbS 4 
Na 3 + 9 Aq, known as Schlippe's salt, forms large, yellow crystals, solu- 
ble in water, and was formerly used in medicine. 



Antimonial Poisoning. 

The compounds of antimony, when taken internally, are poisonous, 
and act with greater or less energy as they are more or less soluble. 
Their poisonous nature was early recognized, and utilized to such an ex- 
tent that in 1566 the French Parliament found it necessary to prohibit 
their use in medicine — a prohibition which was not removed until a cen- 
tury later. 

The compound which is now the most frequent cause of antimonial 
poisoning is tartar emetic (see p. 405), which has proved fatal in a dose 
of one and one-half grain, although recovery has followed the ingestion 
of doses as large as half an ounce in several instances. Indeed, when large 
doses are taken, the chances of recovery seem to be better than after small 
doses, probably owing to the fact that in the former instance the poison is 
more quickly and more completely discharged by vomiting. When ad- 
ministered with murderous intent, antimonials are sometimes given in small 
and often repeated doses, the victim finally dying of exhaustion. When 
the existence of such a case is suspected, the urine should be examined. 

The treatment in acute antimonial poisoning should consist, first, in 
inducing vomiting, if it have not already occurred, by the administration 
of hot water; should this fail to act, the contents of the stomach are to be 
removed by the stomach-pump. When this has been done, tannin in 



138 GENERAL MEDICAL CHEMISTRY. 

some form, decoction of oak-bark, cinchona, nutgalls, strong tea, should 
be given, with a view to the conversion of any remaining poison into an 
insoluble compound. 

The presence of antimony in the viscera is best detected by Marsh's 
test (see p. 132). 

It must not be forgotten that antimony is very liable to contamina- 
tion with arsenic, which, from defective manipulations, may find its way 
into the medicinal antimonials. 



Analytical Reactions. 

Besides the reactions of Marsh's test, the presence of antimony may 
be detected by the following: 1st, the formation of an orange-red pre- 
cipitate when hydrogen sulphide is passed through an acid solution, the 
precipitate being soluble in ammonium sulphydrate and in hot hydro- 
chloric acid; 2d, the formation of a bluish, metallic deposit upon copper 
immersed in a boiling solution, acidulated with hydrochloric acid — the 
stain, when heated in a tube open at both ends, yielding an amorjrfwus 
w T hite sublimate (Reinsh's test). 

The determination of the quantity of antimony is difficult and re- 
quires great care; it should be converted into the oxide, Sb 2 4 , and 
weighed as such. Processes based upon the formation and weighing of 
the sulphide are apt to lead to fallacious results. 



BORIC ACIDS. 139 



IV, BORON GROUP, 

BORON. 

B... A = 11 

This element forms a group by itself, none other being known which 
resembles it in its chemical properties. It is trivalent in all of its com- 
pounds. It forms but one oxide, which is the anhydride of a tribasic 
acid. It forms no compound with hydrogen. 

Boron does not exist as such in nature, but occurs in combination as 
boracic acid and the borates of calcium, magnesium, and sodium. It was 
isolated almost simultaneously by Davy, Gay-Lussac, and Thenard. It 
may be obtained in two allotropic forms — amorphous and crystalline. 

Amorphous boron is obtained by the decomposition of its oxide by 
metallic sodium or potassium. It is a greenish brown powder; sparingly 
soluble in Water, infusible; it unites directly with chlorine, bromine, 
oxygen, sulphur, and nitrogen. 

Crystallized boron is formed when the oxide, chloride, or fluoride is 
reduced by aluminium; or when the amorphous variety is heated with 
aluminium to a high temperature, without contact of air. The product 
varies in color from a deep garnet red to a faint, almost colorless, yel- 
low. The crystals are quadratic prisms, more or less transparent as 
they are lighter or darker in color; very hard and capable of refracting 
light strongly; sp. gr., 2.G8. When strongly heated in oxygen, it first 
swells up, and finally burns at a high temperature. It generally contains 
small quantities of carbon and aluminium. Like amorphous boron, it burns 
readily in an atmosphere of chlorine. It also has a marked tendency to 
combine with nitrogen, being capable, at elevated temperatures, of de- 
composing ammonia, from which it removes the nitrogen, to form the 
nitride, BN, while hydrogen is liberated. It is not dissolved by any acid. 
It forms an alloy, or compound, with platinum, which is much more fusi- 
ble than is that metal. 



Boron Trioxide. 

Boric anhydride — Boracic anhydride — B 2 3 . — This, the only com- 
pound of boron with oxygen, is obtained by heating boric acid to redness 
in a platinum vessel until all water is driven off. The oxide remains on 
cooling as a transparent, glass-like mass, which is used to a limited ex- 
tent in blowpipe analysis. 



Boric Acids. 

Quite a number of acids of boron have been described, either free or 
as salts, all of which are hydrates of the trioxide, and all derivable from 
the tribasic or orthoboric acid, by loss of the elements of water. Of these 
the most important are ortho-, meta-, and tetraboric, or pyroboric, acids. 



140 GENERAL MEDICAL CHEMISTRY. 

Orlhoboric acid — JBoracic acid — Boric acid — B0 3 H 8 — exists in nature 
in volcanic regions, notably in Tuscany. In this region, formerly the main 
source of supply of boracic acid and of borax, jets of steam, known as 
suffioni, escape through fissures in the earth on the hillsides. Over these 
are built a series of shallow basins, through which the vapors are made to 
pass, and from one to another of which water passes slowly by gravity, 
and in its course becomes charged with boracic acid, which is then con- 
verted into borax. 

To obtain the acid, a boiling, concentrated solution of borax is slowly 
decomposed with an excess of sulphuric acid; on cooling the acid crystal- 
lizes out. 

Orthoboric acid is in the form of brilliant, crystalline plates, unctuous to 
the touch; odorless; slightly bitter; soluble in twenty-five parts of water at 
10°; soluble in alcohol, the alcoholic solution burning with a green flame. 
If an aqueous solution of boric acid be distilled, a portion of the acid is 
carried over with the aqueous vapors. Its solution exhibits an acid reac- 
tion with litmus paper, yet it turns turmeric paper brown, a change of 
color produced by the alkalies. 

If orthoboric acid be heated for some time at 80°, it loses the elements 
of a molecule of w T ater, and is converted into metaboric acid, BO a H: 

B0 3 H 3 =H 3 0+B0 3 H. 

If, however, it be heated to about 100° for about eight days, four mole- 
cules unite with loss of five molecules of water: 

4B0 3 H 3 =5H 3 + B 4 7 H 3 . 

Tetraboric acid or Pyroboric acid, B 4 7 H 3 — is a substance of little in- 
terest in itself, but whose sodium salt is the most important compound of 
boron. Another tetraboric acid, B 4 9 H 6 , has also been described. 



Compounds of Boron "with Elements of the Chlorine Group. 

The fluoride, bromide, and chloride have been described. 

Boron fluoride, BF 3 — is prepared by heating together boron trioxide, 
fluor-spar, and sulphuric acid. It is a colorless gas; fuming when exposed 
to the air; very soluble in water, with which it enters into combination, a 
part of the boron separating as boron trioxide, while an acid liquid re- 
mains, which contains hydrqfluoboric acid, BF 4 H. The fluoride is not 
decomposed at a red heat, but is by the alkaline metals in excess, with for- 
mation of an alkaline fluoride and elementary boron. It carbonizes or- 
ganic matter, as does sulphuric acid. 

Boron chloride, BC1 3 — is obtained by heating dry amorphous boron in 
a current of chlorine, and passing the vapors into a well-cooled receiver. 
It is a colorless, mobile liquid; boils at 17°; sp. gr. 1.35. It is capable of 
uniting with ammonia to form a crystalline compound. It is completely 
decomposed by water, with formation of orthoboric and hydrochloric acids. 

Boron bromide, BBr 3 . — Formed by the action of vapor of bromine 
upon a mixture of boron trioxide and charcoal heated to redness. A thick, 
colorless liquid; boils at 90°; sp. gr. 2.69. 



CAKBOK. 141 



V. CARBON GROUP. 

Carbon C 12 

Silicon Si 28 

The two elements composing this group are of great interest, and are 
closely related to each other by resemblances in their chemical and physi- 
cal properties. The} r are both quadrivalent, and form hydrogen com- 
pounds in which one atom of carbon or silicon is combined with four 
atoms of hydrogen. The saturated oxide of each is the anhydride of a 
dibasic acid. They are both solid and combustible, and each occurs in 
three distinct allotropic conditions, one amorphous, one graphitoid, and 
one crystalline. The resemblances existing between their compounds are 
close, so far as they go. But the compounds of silicon with which we 
are acquainted are by no means as numerous as those of carbon, although 
the recent researches of Friedel would indicate that, in this respect also, 
the relationship between the two elements will be found to be close. 

In the following table the analogies between some of the compounds 
of the two elements are shown : 

CH — CO— C0 2 — C0 3 H 2 — CC1 4 — CHC1 3 — CHI 3 — C 2 C1 6 — CS 2 . 
SiH 4 — Si0 3 — Si0 3 H— SiCl— SiHCl— SiHI— Si 2 Cl — SiS 2 . 



CARBON. 
C 12 

An element known from remote antiquity in all its three allotropic 
forms, whose chemical identity and elementary nature were, however, 
first recognized by Lavoisier. It occurs in nature in all of its elementary 
forms, and in combination in the three kingdoms of nature, it being the 
element especially characteristic of such substances as exist only in ani- 
mal and vegetable bodies. 

Its three allotropic forms differ from each other widely in appearance 
and in other physical properties; they occur in nature as : 1st, diamond ; 
2d, graphite; 3d, coal. 

Diamond. — Occurs in nature in octahedral crystals, in India, Brazil, 
Australia, and South Africa. It has also been found in North Carolina 
and in Georgia, in alluvial sand, clay, sandstone, or conglomerate. There 
remains little doubt that diamonds have also been obtained artificially, 
but, owing to our inability to cause the formation to take place under 
proper physical conditions, or to their too rapid formation, diamonds of 
very small size only have been thus far obtained. 

Diamonds are usually colorless or slightly yellowish, sometimes yel- 
low, blue, green, pink, brown, or black. The more faintly colored are 
transparent and have a brilliant lustre or fire, which is enhanced by the 
operation of cutting and polishing, which consists in multiplying the num- 



142 GENERAL MEDICAL CHEMISTRY. 

ber of facets, or surfaces, of the stone, by holding it, suitably supported, 
in contact with a quickly revolving metal plate, coated with oil and dia- 
mond dust. 

The diamond refracts light to a greater degree than any other trans- 
parent solid, and it is chiefly to this property that its great brilliancy is 
clue. Its index of refraction is 2.47 to 2.75. 

It is the hardest known substance, the solid approaching "it most 
nearly in this respect being crystallized boron. It is very brittle, a bad 
conductor of heat and of electricity ; sp. gr. 3.50 to 3.55. When very 
strongly heated in vacuo it swells up, leaving a black mass resembling 
coke; if heated in oxygen it ignites and unites with the oxygen to form 
carbon dioxide. 

Diamonds, whose size, color, or imperfections render them unfit for 
purposes of luxury, are known as bort, and are used, either whole or pow- 
dered, for a variety of purposes in the arts where great hardness is 
required, as in the polishing, drilling, etc., of diamonds and other hard 
stones, in dressing millstones, in cutting glass, etc. 

In weighing diamonds a special arbitrary unit, called the carat, is 
used, which is equivalent to four troy grains, or about 0.25 gram. In 
the cutting a diamond loses two-thirds or more of its weight. The 
largest cut diamond known is the Orloff, belonging to the Emperor of 
Russia, which weighs one hundred and ninety-five carats (one and five- 
eighths ounce) ; it is said to have weighed before cutting seven hundred 
and seventy-nine carats, or nearly six and one-half ounces. 

The diamond is almost pure carbon, containing a mere trace of silex 
and ferric oxide. 

Graphite. — A variety of carbon, almost as free from foreign admix- 
ture as is the diamond, and like it, occurring in the crystalline form, yet 
widely differing from it in its physical properties. 

It is soft enough to be scratched by the nail; crystallizes in hexagonal 
plates; is opaque and of a dark gray color, is greasy to the touch, and 
stains any light-colored substance upon which it is rubbed; is a good 
conductor of electricity, and a better conductor of heat than the diamond. 
It contains from one to two per cent, of impurities. 

Graphite has been obtained artificially. Molten cast-iron dissolves 
carbon to a limited extent, and, if it be allowed to cool slowly, the carbon 
separates in the form of crystals, identical in appearance and properties 
with those of native graphite. These crystals may be separated from the 
iron by dissolving the latter in hydrochloric acid. 

Graphite is extensively mined in England, Siberia, and the United 
States, and is used in the arts, under the names black lead and plumbago, 
in the manufacture of pencils, crucibles, stove-polish, etc., and in electro- 
typing. 

Amorphous carbon exists in nature in enormous deposits, the re- 
mains of vegetable life of past ages, in the form of the different varieties 
of coal, which contain from eight to twenty-five per eent. of substances 
other than carbon. Anthracite coal is hard and dense; it does not flame 
when burning; is difficult to kindle, but gives great heat with a suitable 
draught. It contains eighty to ninety per cent, of carbon, and is some- 
times known as stone-coal. Bituminous coal varies greatly in appear- 
ance, and differs from anthracite in that, when burning, it gives off gases 
which produce a flame. Some varieties are quite soft, while others, such 
Sisjet, which is a kind of lignite, are hard enough to assume a high pol- 
ish. It is usually compact in texture, and very frequently contains im- 



CARBON. 143 

pressions of leaves, fruits, and other parts of vegetables. It contains 
about seventy-five per cent, of carbon. 

Besides these forms in which carbon occurs in nature, it is artificially 
prepared for use in the arts, by the decomposition of substances rich in 
carbon. The kinds of artificial coal differ from each other according to 
the different composition of the substances in whose decomposition they 
have their origin. Ordinary, or vegetable charcoal, is obtained by burn- 
ing woody fibre with an insufficient supply of air, either incidentally in 
the distillation of wood, or as a separate industry. It is brittle and so- 
norous; has the form of the wood from which it was obtained, and retains 
all the mineral matter present in the woody tissue. Its specific gravity 
is about 1.57. It has the power of condensing within its pores odorous 
substances and large quantities of gases: 90 volumes of ammonia, 55 of 
hydrogen sulphide, 9.25 of oxygen. This property is taken advantage 
of in a variety of ways. Its power of absorbing odorous bodies ren- 
ders it valuable as a disinfecting and filtering agent, and in the pre- 
vention of putrefaction and fermentation of certain liquids. It is with 
this view that the interiors of barrels intended to hold wine, beer, or 
water, are carbonized. Certain odorous culinary operations are rendered 
inodorous by the introduction of a fragment of charcoal into the pot. 
The efficacy of charcoal as a filtering material is due also, in a great 
measure, to the oxidizing action of the oxygen condensed in its pores; in- 
deed, if charcoal be boiled with dilute hydrochloric acid, dried, and heated 
to redness, the oxidizing action of the oxygen, which it thus condenses, 
is very energetic. 

Lamp-black is obtained by incomplete combustion of some resinous 
or tarry substance, the smoke or soot from which is directed into suitable 
condensing-chambers. It is a light, amorphous powder, and contains a 
notable quantity of oily and tarry material, from which it may be freed 
by heating in a covered vessel. It is used in the manufacture of printer's 
ink. 

Coke is the substance remaining ifi gas-retorts after the distillation of 
bituminous coal in the manufacture of illuminatin^-o-as. As all sub- 
stances capable of yielding gases when heated have been driven off, coke 
does not possess the property of flaming when burned. It is a hard, gray- 
ish substance, usually very porous, dense, and sonorous. When iron re- 
torts are used, a portion of the gaseous products are decomposed by con- 
tact with the hot iron surface, upon which there is then deposited a layer 
of very hard, compact, grayish carbon, which is a good conductor of elec- 
tricit} 7- , and furnishes the best material for making the carbons of galvanic 
batteries and the points for the electric light. It does not form when 
gas is made in clay retorts. 

Animal charcoal is obtained by calcining animal matters in closed ves- 
sels; if prepared from bones it is known as bone-black; if from ivory, ivory- 
black y the latter is used as a pigment, the former as a decolorizing agent. 
Bones yield about sixty per cent, of bone-black, which contains, besides 
carbon, nitrogen and the phosphates, and other mineral substances of the 
bones. It possesses in a remarkable degree the power of absorbing 
coloring matters, for which purpose it is largely used in sugar-refining. 
When its decolorizing power is lost by saturation with pigmentary bodies, 
it may be restored, although not completely, by calcination. For certain 
purposes in the laboratory purified animal charcoal, i. e., freed from min- 
eral matter, is required, and is obtained by extracting the commercial 
article with hydrochloric acid and washing it thoroughly; its decolorizing 



144 GENERAL MEDICAL CHEMISTRY. 

power is diminished by this treatment. Animal charcoal has the power 
of removing from a solution certain crystalline substances, notably the 
alkaloids, and a method has been suggested for separating these bodies 
from organic mixtures by its use. 

The most notable chemical property of carbon is the readiness with 
which it unites with oxygen at high temperatures — a property of the ele- 
ment not only in its three simple forms, but also in most of its com- 
pounds. The product of the union is carbon dioxide, if the supply of 
oxygen is sufficient; if oxygen be present in more limited quantity, carbon 
monoxide is formed. 

The affinity of carbon for oxygen renders it a most valuable reducing 
agent. Many oxides, when heated with charcoal, are reduced with for- 
mation of carbon dioxide: 



2CuO + C = 


2Cu 


+ CO, 


Cupric Carbon, 
oxide. 


Copper. 


Carbon 
dioxide. 



The reducing power of oxygen is utilized in many processes in the 
arts, as in the working of iron and other ores. 

If a current of steam be passed over strongly heated coke, the watery 
vapor is reduced, hydrogen and carbon monoxide being formed — 

H 2 + C=CO+H 2 , 

a reaction utilized in the manufacture of an illuminating gas, known as 
water-gas. 

At elevated temperatures, about 1000°, carbon also unites directly 
with sulphur to form a volatile liquid — carbon disulphide. 



COMPOUNDS OF CARBON. 145 



COMPOUNDS OF CARBON. 

Organic Substances. 

In the seventeenth and eighteenth centuries, chemists had observed 
that there miixht be extracted from animal and vegetable bodies substances 
which differed much in their properties from those which could be ob- 
tained from the mineral world; substances which burned without leav- 
ing a residue, and many of which were subject to the peculiar changes 
wrought by the processes of fermentation and putrefaction. It was not 
until the beginning of the present century, however, that chemistry was 
divided into the two sections of inorganic and organic. 

In the latter class were included all such substances as existed only in 
the organized bodies of animals and vegetables, and which seemed to be 
of a different essence from that of mineral bodies, as chemists had been 
unable to produce any of these organic substances by artificial means. 
Later in the history of the science it was found that these bodies were all 
made up of a very few elements, and that they all contained carbon. 
Gmelin at this time proposed to consider as organic substances all such as 
contained more than one atom of carbon, his object in thus limiting the 
minimum number of atoms of carbon being that substances containing one 
atom of carbon, such as carbonic acid and marsh-gas, were formed in the 
mineral kingdom, and consequently, according to then existing views, 
could not be considered as organic. Illogical as such a distinction is, we 
find it still adhered to in text-books of very recent date. 

The notion that organic substances could only be formed by some mys- 
terious agency, existing only in organized beings, was finally exploded by 
the labors of Wohler and Kolbe. The former obtained urea from ammo- 
nium cyanate; while the latter, at a subsequent period, formed acetic 
acid, using in its preparation only such unmistakably mineral substances 
as coal, sulphur, aqua regia, and water. 

During the half-century following Wohler's first synthesis, chemists 
have succeeded not only in making from mineral materials many of the 
substances previously only formed in the laboratory of nature, but have 
also produced a vast number of carbon compounds which were previously 
unknown, and which, so far as we know, have no existence in nature. At 
the present time, therefor, we must consider as an organic substance any 
compound containing carbon, whatever may be its origin and whatever its 
properties. Indeed, the name organic is retained merely as a matter of 
convenience, and not in any way as indicating the origin of these com- 
pounds. Although, owing to the great number of the carbon compounds, 
it is still convenient to treat of them as forming a section by themselves, 
their relations with the compounds of other elements is frequently very 
close; indeed, within the past few years, compounds of silicon have been 
obtained, which indicate the possibility that that element is capable of 
forming series of compounds as interesting in numbers and variety as 
those of carbon. 

Nevertheless, there are certain peculiarities exhibited by carbon in its 
compounds, which are not possessed to a like extent by anv other element, 
10 



146 GENERAL MEDICAL CHEMISTRY. 

and which render the study of organic substances peculiarly interesting" 
and profitable. 

In the study of the compounds of the other elements, we have to deal 
with a small number of substances, relatively speaking, formed by the 
union with each other of a large number of elements. With the organic 
substances the reverse is the case; for, although compounds have been 
formed which contain carbon along with each of the other elements, the 
great majority of the organic substances are made up of carbon, combined 
with a very few other elements, hydrogen, oxygen, and nitrogen occurring 
in them most frequently. 

It is chiefly in the study of the carbon compounds that we have to deal 
with radicals (see p. 17). Among mineral substances there are many 
whose molecules consist simply of a combination of two atoms; among 
organic substances there is none which does not contain a radical; indeed, 
organic chemistry has been defined as " the chemistry of compound 
radicals." 

The atoms of carbon possess in a higher degree than those of any other 
element, silicon possibly excepted, the power of uniting with each other, 
and in so doing of interchanging valences. Were it not for this property 
of the carbon atoms, we could have but one saturated compound of carbon 
and hydrogen, CH 4 , or, expressed graphically: 

H 

H— C— H. 

I 
H 

There exists, however, a great number of such compounds, which differ 
from each other by one atom of carbon and two atoms of hydrogen. In 
these substances the atoms of carbon may be considered as linked together 
in a continuous chain, their free valences being satisfied by atoms of hy- 
drogen; thus: 

H H H H 

H— C— C— C— C— H 

I I I I 
H H H H 

If now one atom of hydrogen be removed from either of these combina- 
tions, we have a group possessing one free valence, and consequently 
univalent. The decompositions of these substances show that they con- 
tain such radicals, and that their typical formulse are: 



H 

1 


H H 

1 | 


H— C— H 

i 


H— C— C— H 

i i 


! 
H 


1 1 
H H 



CH. 
H 



\ . C 2 H 5 ) . C 4 H 9 ) 

\> H p H [' 



Homologous Series. 

It will be observed that these formulse differ from each other by CH 2 , 
or some multiple of CH 2 , more or less. In examining numbers of organic 
substances, which are closely related to each other in their properties, we 



COMPOUNDS OF CARBON. 



147 



find that we can arrange the great majority of them in series, each term 
of which differs from the one below it by CH 2 ; such a series is called an 
homologous series. It will be readily understood that such an arrange- 
ment iii series vastly facilitates the remembering of the composition of 
organic bodies. In the following table, for example, are given the satu- 
rated hydrocarbons and their more immediate derivatives. At the head 
of each vertical column is an algebraic formula, which is the general 
formula of the entire series below it; n being equal to the numerical 
position in the series. The chemist is not obliged to burden his memory 
with all the formulae in the table, but simply to remember the algebraic 
formulae. The name of the substance conveys, in most instances, to his 
mind the series to which it belongs, and its position in that series; and 
by the aid of the algebraic formula, or general formula as it is called, its 
composition is found in a moment. 



Homologous Series. 



Saturated hydro- 
carbons, 
CnH 2 u+2' 


Alcohols, 


Aldetrydes, 


Acids, 


Ketones, 


CnH a n+ 2 0. 


CnH 2a O. 


CnH 3 n0 2 : 


CnH 2 uO. 


CH 4 


CH 4 




CO2H2 




C,H 6 


C 2 H 6 


C 2 H 4 


C 2 2 H 4 




C 3 H 3 


C 3 H*0 


C 3 H e O 


C 3 2 H 6 


C 3 H 6 


C4H10 


C 4 H 10 O 


C 4 H fe O 


C 4 2 H 8 


C 4 H 8 


C 5 H 12 


C 5 H 12 


C 5 H lu O 


CsO.-Hk) 


C5H10O 


C 6 Hn 


C 6 H 14 


6 H 15 O 


C 6 2 Hi 2 




C 7 H 16 


C 7 H 16 


C 7 H 14 


C70 2 Hi 4 




CtHis 


CgHisO 


C 8 H 16 


CsOiHis 




C9II20 


CgEUoO 




C 3 3 H 18 




C ( 0H22 


\J\§IX<11\J 




CiuOoHoo 




C11H24 










C12H26 






C12O2H04 




C13H28 










C14H30 






Ci 4 2 H 28 





But the arrangement in homologous series does more for us than this. 
The properties of substances in the same series vary in regular gradation 
according to their position in the series; thus, in the series of alcohols in 
the above table, the boiling-points of the first six are, 66.5°, 78.4°, 96.7°, 
111.7°, 132.2°, 153.9°; from which it will be seen that the boiling-point 
of any one of them can be determined, with a maximum error of 3°, by 
taking the mean of those of its neighbors above and below. In this way 
we may prophecy, to some extent, the properties of a wanting member 
in a series before its discovery. The terms of any homologous series 
must all have the same constitution, i. e., their constituent atoms must be 
similarly arranged within the molecule. 



Isomerism — Metamerism — Polymerism. 

Two substances are said to be isomeric, or to be isomeres of each other, 
when, upon analysis, they prove to have the same centesimal composition. 
If, for instance, we analyze acetic acid and methyl formiate, we find that 



148 GENERAL MEDICAL CHEMISTRY. 

each body consists of carbon, oxygen, and hydrogen, in the following 
proportions: 

Carbon 40 24=12 x 2 

Oxygen 53.33 32=16x2 

Hydrogen < 6 . 67 4=4x1 

100.00 60 

This similarity of centesimal composition may occur in two ways: 
the two substances may each contain in a molecule the same numbers of 
each kind of atom ; or one may contain in each molecule the same kind of 
atoms as the other, but in a higher multiple. In the above instance, for 
example, each substance may have the composition C 2 H 4 2 ; or one may 
have that formula and the other, C 6 H 12 O c , or C 2 H 4 2 x 3. In the former 
case the substances are said to be metameric, in the latter polymeric. 
Whether two substances are metameric or polymeric can only be de- 
termined by ascertaining the weights of their molecules, which is usually 
accomplished by determining the specific gravities of their vapors (see 

p- 14 >- 

The specific gravity of the vapor of acetic acid is the same as that of 
methyl formiate, and, consequently, each substance is made up of mole- 
cules, each containing C 2 H 4 2 . But the two substances differ from each 
other greatly in their properties, and their differences are at once indi- 
cated by their typical or graphic formulas: 

WOJfo and (CHO) ; [ 0; 

or graphically: 

CH, H 

and 
COO.H CO.OCH 3 . 

Polymeric substances, although they yield the same result upon cen- 
tesimal analysis, possess different molecular weights, that of one being a 
simple multiple of that of the other. Acetic acid and grape-sugar, on 
analysis, both prove to have the same centesimal composition: 

Carbon 40. 12 

Oxygen 53 . 33 16 

Hydrogen 6.67 2 

100.00 30 

but the molecular weight of acetic acid is 60, or 12x2 + 16x2 + 1x4, 
and its composition is therefor C 2 2 H 4 . The molecule of grape-sugar 
weighs 180, or 12x6 + 16x6 + 1x12, and its composition is therefor 
C.O.H u . 

Classification of Organic Substances. 

As the compounds of the other elements may be divided into classes, 
such as acids, bases, salts, etc., according to their chemical functions, the 



COMPOUNDS OF CARBON. 149 

compounds of carbon also arrange themselves into certain well-defined 
groups, called by trie French chemists functions — a term which it would 
be well to introduce into our own nomenclature. The properties of the 
functions of organic substances do not depend, like those of other com- 
pounds, upon the kind of atoms of which they are composed, but rather 
upon the arrangement of the atoms within the molecule; and in this 
point we find the most prominent distinction between organic and mineral 
substances. Arsenic, for instance, is poisonous in whatever form of 
chemical combination it may be, provided only that it can be rendered 
soluble, and therefor capable of absorption. Carbon, oxygen, and hydro- 
gen, on the other hand, combine with each other to form substances hav- 
ing the most diverse action upon the economy — the fats and sugars, 
ordinary articles of food, on the one hand, and substances having such 
marked toxic powers as ether and oxalic acid, on the other — the differ- 
ences between the properties of the two substances depending entirely 
upon the numbers and positions in the molecule of the same kind of atoms. 
Before entering upon the consideration of the individual compounds, 
and to render what follows intelligible, we must briefly describe the gen- 
eral properties of these different functions. 



Derivatives of the Saturated Hydrocarbons — Compounds op Uni- 
valent Radicals. 

Saturated hydrocarbons. — A hydrocarbon is a compound consisting 
of carbon and hydrogen only, and it is saturated when all the valences of 
the constituent atoms are satisfied. These substances belong to the 
homologous series of which marsh-oras is the first term, and which has 
the general formula, CJH 2n+2 . Like all other saturated compounds, 
their composition cannot be modified by addition, i. e., by the simple in- 
sertion of other atoms into the molecule; they may, however, be modified 
by substitution, i. e., by the removal of one or more of their atoms, and 
the substitution therefor of one or more atoms of a different kind; Their 
composition is expressed by the typical formula: 

C n H 2D+1 ) (CHJ ) 

H \ e - g - H[ 

The groups C n H 9n+1 , containing one unsatisfied valence, are univa- 
lent, and are the radicals of which these hydrocarbons are the hydrides. 
These univalent radicals, more or less modified by substitution, enter into 
the composition of a vast number of important substances, which are thus 
said to be derivatives of this series of hydrocarbons. These radicals are 
also sometimes designated as alcoholic, as they exist in the series of sub- 
stances of which ordinary alcohol is the type. The members of this series 
are sometimes called paraffines, from the occurrence of the higher terms 
in the commercial product of that name and in petroleum. 

Chlorides, Bromides, and Iodides. — The radicals of this series behave 
in many respects like atoms of a univalent, electro-positive element, and, 
like them, are capable of uniting with an atom of chlorine, bromine, or 
iodine, to form chlorides, bromides, or iodides. 

(C,H 5 ) 'H + Br, = (C,H s )'Br + BrH 

Ethyl Bromine. Ethyl Hydrogen 

hydride. bromide. bromide. 



150 GENERAL MEDICAL CHEMISTRY. 

These substances are also designated as haloid ethers, corresponding, 
as they do, with the haloid salts. Several of them are used medicinally. 

Alcohols. — The name alcohol, formerly applied only to the substance 
now popularly so called, has gradually come to be used to designate a 
large class of important bodies, of which vinic alcohol is the representa- 
tive. These substances are mainly characterized by their power of enter- 
ing into double decomposition with acids, to form neutral compounds, 
called compound ethers, water being at the same time formed, at the 
expense of both alcohol and acid. They are the hydrates of the alcoholic 
radicals, and as such resemble the metallic hydrates, while the compound 
ethers are the counterparts of the metallic salts: 



Ethyl hydrate. Acetic acid. 


Ethyl acetate. Water 


i}o + ( c . H #}o = 


= (CAO)J 0+ H| 


Potassium Acetic acid, 
hydrate. 


Potassium Water, 
acetate. 



As the metallic hydrates may be considered as formed by the union 
of one atom of the metallic element with a number of groups OH', cor- 
responding to its valence, so the alcohols are formed by union of an un- 
oxidized radical with a number of groups OH', equal to or less than the 
number of free valences of the radical. When the alcohol contains one 
OH, it is designated as monoatomic; when two, diatomic; when three, 
triatomic, etc. 

The simplest alcohols are those derivable from the saturated hydro- 
carbons, and having the general formula C n H Q „ +2 0, or C n Ii 2n+1 OH. The 
terms of this series, which contains vinic alcohol, may be formed synthet- 
ically : 

First. — By acting upon the corresponding iodide with potassium hy- 
drate: 

C 2 HJ+KHO=KI+C 2 H 6 OH. 

Second. — From the alcohol next below it in the series, by direct addi- 
tion of CH 2 , only, however, by a succession of five reactions. 

Third. — By the action of sulphuric acid and water upon the corre- 
sponding hydrocarbon of the series C w H 2n . 

The saturated monoatomic alcohols are, however, not limited to one 
corresponding to each alcoholic radical. It has been found that there 
exist — corresponding to the higher alcohols — a number of substances 
having the same centesimal composition and the same alcoholic prop- 
erties, and differing only in their physical characters and in their pro- 
ducts of decomposition and oxidation. These isomeres have been the 
subject of much careful study of late years. It has been found that the 
molecules of methvl, ethyl, and other higher alcohols are made up of the 
group (CH 2 OH)' united to H or to C n H 2 „ +1 , thus: 

CH 2 OH CH 2 OH CH.OH 

H CH 3 C 2 H 5 

Methyl alcohol. Ethyl alcohol. Propyl alcohol. 



COMPOUNDS OF CARBON. 151 

and all monoatomic alcohols containing this group, CH 2 OH, have been 
designated as primary alcohols. Isomeric with these are other bodies, 
which, in place of the group (CH 2 OH)', contain the group (CHOH)", 
which are distinguished as secondary alcohols. Thus we have: 

CH 3 
(CH 2 OH)' | 

| (CHOH)" 

C.H. | 

CH 3 

C 3 H 8 C 3 H 8 

Primary Secondary 

propyl alcohoL propyl alcohol. 

And, further, other substances are known, which contain the group 
(COH)"', and which are called tertiary alcohols, thus: 

(CH 2 OH)' C 2 H 6 CH S 

C 4 H 9 (CHOH)" (C 2 H 6 )— (COH)'" 

C„H C CH 



2 5 



C.H.,0 C s H„0 C 5 H 12 

Primary amylic Secondary amylic Tertiary amylic 

alcohol. alcohol. alcohol. 

The alcohols of these three classes are distinguished from each other 
principally by their products of oxidation. The primary alcohols yield 
by oxidation, first an aldehyde and then an acid, each containing the 
same number of atoms of carbon as the alcohol, and formed, the aldehyde 
by the removal of H 2 from the group (CH 2 OH), and the acid by the sub- 
stitution of O for H 2 in the same group, thus: 



CH 2 OH COH COOH 

1 J I 

CH 3 CH, CH 3 

Ethyl alcohoL Ethyl aldehyde. Acetic acid 



In the case of the secondary alcohols, the first product of oxidation is a 
ketone, containing the same number of atoms of carbon as the alcohol, and 
formed by the substitution of O for HOH in the distinguishing group: 

CH 8 CH S 

CHOH CO 

I I 

CH 3 CH 3 

Secondary propyl Propyl ketone 

alcohol. or acetone. 

The tertiary alcohols yield by oxidation ketones or acids, whose mole- 
cules contain a less number of atoms of carbon than the alcohol from 
which they are derived. 



152 GENERAL MEDICAL CHEMISTRY. 

But the complication does not end here; isomeres have been found to 
exist corresponding- to the higher alcohols, which are themselves primary 
alcohols, and contain the group (CH 2 OH)'. It has been shown by recent 
investigation that there exist no less than seven distinct substances, all 
having the centesimal composition of amyl alcohol, C 5 H 12 0, and the prop- 
erties of alcohols; and theoretical considerations point to the probable ex- 
istence of an eighth. Of these eight substances, four are primary, three 
secondary alcohols, and the remaining one a tertiary alcohol. As each of 
these bodies contains the group of atoms characteristic of the class of 
alcohol to which it belongs, it is obvious that the differences observed in 
their properties are due to differences in the arrangement of the other 
atoms of the molecule. Experimental evidence, which it would require 
too much space to discuss in this place, has led chemists to ascribe the 
following formulae of constitution to these isomeres: 

Primary amylic alcohols: 

CH— CH — CH — CH — CH 2 ,OH 

Normal amylic alcohol. 

CH/ CH— CH »— CH 2 > 0H 

Active amylic alcohol of fermentation. 

ch,-c!:> ch - ch *> oh 

Inactive amylic alcohol of fermentation. 



CH 3 \ 

CH, 

CH 



CH„— C— CH 2 ,OH 



3/ 

Unknown. 



Secondary amylic alcohols: 

ch:=ch;> ch > oh 

Diethyl carbinol. 

3^-PTT OTT 

CH— CH— CH a / u±1 ' u±1 

Methyl-propyl carbinol. 

CH 3\CH^ CH ' 0H 
CH 8 / 0±1 / 

Methyl-isopropyl carbinol. 

Tertiary amyl alcohol : 

CH,\ 
CH,— C,OH 
CH.-CH,/ 

For alcohols of other series, see pp. 230, 274. 

Simple Ethers. — These bodies are the oxides of the alcoholic radicals, 



COMPOUNDS OF CARBON. 153 

and in constitution bear the same relation to the alcohols that the oxides 
of basylous elements bear to their hydrates: 

C 2 HJ Hf U 

Ethyl oxide Ethyl hydrate 

(ethylic ether). (alcohol). 

Potassium oxide. Potassium hydrate. 

When the two alcoholic radicals are the same, as in the above in- 
stance, the ether is designated as simple; when they are different, as in 

methyl-ethyl oxide, n u 3 [ O, they are called mixed ethers. 

Monobasic Acids. — By the action of oxidants upon the primary mono- 
atomic alcohols, one atom of oxygen is substituted for H 2 in the group 
CH 2 OH, with the formation of substances having the functions of acids, 
and containing in each molecule one atom of replaceable hydrogen: 

CH 3 — CH — CH — CH — CH 2 ,OH 

Normal amy lie alcohol. 

CH— CH— CH— CH— CO,OH 

Normal valerianic acid. 

The introduction of the atom of oxygen communicates electro-nega- 
tive qualities to that portion of the molecule other than OH, to the radi- 
cal; in other words: 

Amylic alcohol. Valerianic acid. 

And it is to this electro-negative nature of the radical, that the substance 
owes its acid nature. 

The acids formed by the oxidation of the primary alcohols, have the 
general formula 

C w H 2n 2 , or C » H ^°!-0 

Compound Ethers. — As the alcohols resemble the mineral bases, and 
the organic acids resemble those of mineral origin, so the compound 
ethers are similar in constitution to the salts, being formed by the double 
decomposition of an alcohol with an acid, mineral or organic, as a salt 
is formed by double decomposition of an acid and a mineral base, the 
radical playing the part of an atom of corresponding valence. 



Potassium hydrate. Nitric acid. Water. Potassium nitrate. 



154 



GENERAL MEDICAL CHEMISTRY. 



(WJ + (NO,J = H [o + & 0,)J 



Ethyl hydrate 
(alcohol). 



Nitric acid. 



(W)o + ™jo 



Ethyl hydrate. 



Acetic acid. 



Water. 



Water. 



Ethyl nitrate 
(nitric ether,). 



? I o + (<W>)' > Q 



Ethyl acetate 
(acetic ether). 



Aldehydes. — It will be remembered that the monobasic acids are 
obtained from the alcohols bv oxidation of the radical: 



(C,H.) 
H 



O 



Ethyl alcohol. 



<c,H 3 oy j 



Acetic acid. 



These oxidized radicals are capable of forming compounds similar in con- 
stitution to those of the non-oxidized radicals. There are chlorides, bro- 
mides, and iodides ; their hydrates are the acids, ^ 2 3 J [■ O, = acetic 

acid; their oxides are known as anhydrides, )r?Tj*(Y\ C ® = ace tic anhy- 
dride ; and their hydrides are the aldehydes ^ 2 3 U I = acetic aldehyde, 

the name aldehyde being a corruption of alcohol dehydrogenatum, from 
the method of their formation, by the removal of hydrogen from alcohol. 
The aldehydes all contain the group of atoms (COH)', and their con- 
stitution may be thus graphically indicated : 





COH 


COH 


I 


I 


CH 2 


CH 3 


| 




CH 3 


Acetic aldehyde. 


Propionic aldehyde. 



They are capable, by fixing H 2 , of regenerating the alcohol ; and, by 
fixing O, of forming the corresponding acid: 



COH 

1 


CH 2 OH 

1 


CO,OH 

i 


OH, 


CH 3 


CH 3 


Acetic aldehyde. 


Ethylic alcohol. 


Acetic acid. 



Ketones or Acetones. — Although the aldehydes are not acid in reaction, 
and are not usually regarded as acids, there exists a number of substances 
known as ketones or acetones, which may be regarded as formed by the 
substitution of an alcoholic radical for the hydrogen of the group COH, 



COMPOUNDS OF CAEBON. 



155 



These substances all contain the group of atoms (CO)", and their con- 
stitution may be represented graphically thus : 



CH, 
CO 

CH. 



Dimethyl ketone 
(acetone). 



CH 3 

I 
CO 

I 

CH 2 

i 

i 

CH, 

Methyl-ethyl ketone. 



The first being a symmetrical ketone and the latter a non-symmetrical. 
The ketones are isomeric with the aldehydes, from which they are dis- 
tinguished : 1st, by the action of hydrogen, which produces a primary 
alcohol with an aldehyde, and a secondary alcohol with a ketone: 



COH 




CH 2 OH 

1 


CH, + 


H, 


1 

= CH 2 
1 


CH, 

Propionic aldehyde. 




CH, 

Propyl alcohol. 


CH, 

1 




| 3 


CO + 
1 


H 2 


i= CH,OH 

i 


CH, 

Acetone. 




CH, 

Isopropyl alcohol 



2d, by the action of oxygen, which unites directly with an aldehyde to 
produce the corresponding acid, while it causes the disruption of the mole- 
cule of a ketone, with formation of two acids: 



COH CO,OH 

I I 

CH, + O = CH, 



CH, 


CH, 


Propionic aldehyde. 


Propionic acid. 


CH, 

1 

CO + 0, = 

1 

CH, 


CO,OH CO,OH 

1 +1 
H CH 3 



Acetone. 



Formic acid. 



Acetic acid. 



Amines or compound ammonias. — The monamines are substances 
which may be considered as being derived from one molecule of ammonia 
by the substitution of one, two, or three alcoholic radicals for one, two, or 



156 GENERAL MEDICAL CHEMISTRY. 

three atoms of hydrogen. They are designated as primary, secondary, 
and tertiary, according as they contain one, two, or three alcoholic radicals: 

H H H CH -CH 3 

II I I 

N-H N-CH -CH 3 N-CH-CH 3 N-CH -CH, 

I III 

H H CH 2 -CH 3 CH.-CH, 

NH 3 (C 2 H 5 )H 2 ,N (C 3 H B ) 3 H,N (C 2 H 6 ) 3 N, 

Ammonia. Ethylamine Diethylamine Triethylamine 

(primary). (secondary). (tertiary). 

These bodies closely resemble ammonia in their chemical properties ; 
they unite with acids, without elimination of water, to form salts resem- 
bling those of ammonium. They also unite with water to form com- 
pounds, called quaternary ammonium hydrates, similar in constitution 
to ammonium hydrate. 

Although the amines of this series are chiefly of theoretical interest, 
other series contain substances of great practical importance (see p. 346). 

Amides. — These bodies differ from the amines in containing oxygen- 
ated, or acid radicals, in place of alcoholic radicals. Like the amines, 
they are divisible into primary, secondary, and tertiary. They are the 
nitrides of the acid radicals, as the amines are the nitrides of the alcoholic 
radicals. 

The monamides may also be regarded as the acids in which the OH of 
the group COOH has been replaced by (NH 2 ): 

CH 3 CH 3 

I J 

COOH CONH 3 

Acetic acid. Acetamide. 

(For other amides see p. 256.) 

Amido-acids or Glycocols. — These are compounds of mixed function, 
obtained by the substitution of the univalent group (NH 2 )', for an atom 
of radical hydrogen of an acid: 

CH 3 CH 2 (NH a ) 



A, 



^OOH COOH 

Acetic acid. Amido-acetic acid ; glycocol. 

Some of them, and many of their derivatives, exist in animal bodies. 
Corresponding to them are many isomeres belonging to other series. 



METHYL HYDRIDE. 



157 



SATURATED HYDROCARBONS. 



Series C k H 



n^-"^-^ 



The members of this series are the most simply constituted of organic 
substances. They exist in nature chiefly as products of what is com- 
monly regarded as the mineral kingdom, and constitute the inflammable 
gases and rock-oils which issue from the earth in Pennsylvania, Russia, 
and other places. 

The following is a list of the members of this group at present known: 



Name. 


Formula. 


Specific gravity of 
liquid. 


Boiling-point. 
Centigrade. 


Methyl hydride 


CH S H 

C 2 H S H 

C 3 H 7 H 

C.H.H 

C 6 H n H 

C 6 H„H 

C 7 H 15 H 

C 8 H„H 

9 H„H 

C ,0 H 21 H 

C,A,H 
C 12 H, 6 H 
C IS H 37 H 
C„H a ,H 
C I6 H 3I H 
O le H M H 


0.600 at 0° 
0.628 at 18° 
0.669 at 18° 
0.690 at 18° 
0.726 at 18° 
0.741 at 18° 
0.757 at 18° 
0.766 at 18° 
0.778 at 18° 
0.796 at 18° 
0.809 at 18° 
0.825 at 18° 




Ethyl hydride 




Butyl hydride 


0° 


Amyl hydride 


30° 


Hexyl hydride 


68° 


Heptyl hydride 


92°— 94° 


Octyl hvdride 


116°— 118° 


Nonvl hvdride 


136°— 138° 


Decyl hvdride 


158°— 162° 


Pentadecyl hydride 


180°— 182° 
198°— 200° 
218°— 220° 
236°— 240° 
258°— 262° 
about 280° 



in 



Methyl Hydride. 

Methane — 3Iarsh-gas — Light carburetted hydrogen — Fire-damp 

CH 4 or ^ tj >- . — It is given off from decomposing vegetable matter 

swamps and bogs. Yolta, in 1778, first recognized the individuality of 
the inflammable gas observed in such situations. 

The fire-damp, which has been the cause of such terrible loss of life 
in coal-mines,, is a mixture composed almost entirely of methyl hydride 
and air, in varying proportions. In many localities in the vicinity of 
coal or petroleum deposits, and in some instances at considerable dis- 
tances from such formations, there issue large volumes of inflammable 
gases from fissures and borings in the earth. These gases consist of methyl 
hydride, mixed with the higher members of the series. If the latter be 
present in notable proportions, the flame of the gas is luminous, and may 
be utilized for illuminating purposes. Illuminating gas, obtained from 



158 GENERAL MEDICAL CHEMISTRY. 

the distillation of coal, contains from thirty-six to fifty per cent, of this 
gas (see p. 287). 

When desired in a state of purity, marsh-gas is best obtained by heat- 
ing strongly a mixture of sodium acetate and sodium hydrate, each one 
part, and quicklime one and one-half parts, and collecting the gas over 
water: 

C a H 3 2 Na + NaHO = C0 3 Na a + CH 4 . 

Methyl hydride is a colorless, odorless, tasteless gas; very sparingly 
soluble in water; more soluble in alcohol; sp. gr. 0.559A. 

Like all the members of this series, marsh-gas is a very stable sub- 
stance, and is not readily attacked by reagents; it is for this reason that 
the name paraffines (from parum, little, and affinis, related to by mar- 
riage) has been applied, particularly to the higher terms of the series, and 
recently to the entire series. 

At high temperatures it is decomposed into carbon and hydrogen: 

CH 4 = C + 2H 3 . 

Its decomposition takes place at much lower, but still elevated, temper- 
atures when it is mixed with air or oxygen. It burns in air with a pale 
yellow flame, which is extinguished when cooled. Advantage is taken of 
this in the construction of miners' safety-lamps, in which the flame is en- 
closed in a cage of fine wire-gauze, which, by its cooling effect, prevents 
the transmission of flame from the lamp outward. If a mixture of marsh- 
gas and oxygen (or air) be heated at a single point by the passage of the 
electric spark, or by the approach of a flame, instant decomposition of the 
entire mass takes place, with a violent explosion, and the formation of 
carbon dioxide and water: 

CH 4 +20 a =CO a +2H 3 0. 

The formation of immense volumes of carbon dioxide in this way, in mine- 
explosions, produces what is known to miners as after-damp, usually fatal 
to those who have escaped the violence of the explosion itself. 

Chlorine has no action upon marsh-gas in the dark and cold; under 
the influence of diffuse davlig-ht, however, one or more of the atoms of 
hydrogen are replaced by an equivalent quantity of chlorine. In direct 
sunlight the change takes place with an explosion. The higher terms of 
this series are of interest principally as constituting petroleum and allied 
bodies obtained therefrom. 



Petroleum. 

(From irirpa, a rock, and oleum, oil.) Mineral oils have been known 
from the remotest antiquity, and were obtained from the vicinity of Agri- 
gentum, in Sicily, from the Island of Zacynthus, in the Ionian Sea, and 
from Persia, for use as a medicine and for burning in lamps. In later 
times petroleum was found in various parts of Europe, Asia, and South 
and North America. It is only, however, since 1859 that rock-oil has be- 
come the commercially important substance that it now is. In 1853 at- 
tention was first drawn to the existence of petroleum in Pennsylvania, and 
from that date until 1859 attempts were made to obtain the oil by the old 



PETROLEUM. 159 

Indian method of sinking square pits into the earth, in which cloths were 
then placed until saturated with the oil, which was then wrung out. 

In 1859 the oil fever was inaugurated with the sinking of a well sev- 
enty-five feet deep near Titusville, from which ten barrels or four hundred 
and thirty gallons of oil were obtained daily. A great number of wells 
were now sunk at various points in the Oil Creek Valley, and with such 
success that the production during the first year amounted to eighty-two 
thousand barrels, or over three and one-half millions of gallons. From 
that time to the present the production of oil has steadily increased. 

The production is not limited to Pennsylvania, large quantities being 
obtained from Ohio, Western New York, West Virginia, Lower Canada, 
as well as from California, Burmah, Borneo, and the shores of the Caspian 
Sea. The oil obtained in different localities varies in composition. In 
the American oil districts the oil is obtained from either flowing or pump- 
ing wells, the former of which yield enormous quantities of oil, but cease 
flowing after a time. The famous Empire well flowed from 1862 to 1866, 
and yielded two thousand barrels, or eighty-six thousand gallons, per 
diem. In its deposits the oil is associated with salt water and gaseous 
hydrocarbons, forming a layer upon the surface of the water. When the 
deposit occurs in a closed jiocket, the pressure of the gas is sufficient to 
force through a tube penetrating the cavity either water, oil, or gas, as 
the end of the tube is in one or another layer. 

The crude petroleum, as it comes from the well, is a highly inflammable 
substance, differing in composition and in physical properties in the 
products of different wells, even in the same section of country. It varies 
in color from a faintly yellowish tinge to a dark brown, nearly black, 
with greenish reflections. The lighter-colored varieties are limpid, and 
the more highly colored of the consistency of thin syrup. The specific 
gravity varies from 0.74 to 0.92. The composition of crude petroleums 
has been the subject of a great deal of investigation; they have been 
found to contain all the hydrocarbons mentioned in the list on p. 157, 
(the first of the series, being found in the gases accompanying petroleum, 
is also held in solution by the oil under the pressure it supports in natural 
pockets), besides hydrocarbons of the olefine series (see p. 227), and of 
the benzol series (see p. 315). 

The crude oil is highly inflammable, usually highly colored, and is 
prepared for its multitudinous uses in the arts by the processes of dis- 
tillation and refining; which, in the case of the American oils, are con- 
ducted at the three principal refineries at Cleveland, O., New York, and 
Pittsburg, Pa., to w r hich points the mixed oils from various wells are 
conveyed by boat, rail, or lines of pipes. 

The process of distillation is usually so conducted as to divide the 
crude oil into four parts: 

Naphtha sp. gr. 0.700 at 15° C 12—15 per cent. 

Benzine sp. gr. 0.730 at 15° C 9 — 12 per cent. 

Burning-oil. . . .sp. gr. 0.783 at 15° C. about 60 per cent. 

Mesiduum and loss about 13 — 19 per cent. 

The naphtha, also known as petroleum ether, is by further fractional 
distillation again subdivided into other products: 

Bhigolene, a highly volatile and inflammable liquid, which boils at 
21° C. = 70° F., and has a specific gravity of about 0.60 = 90°— 97° 
Baume. It has been used as a substitute for ether to produce cold by 



100 GENERAL MEDICAL CHEMISTRY. 

evaporation. It should be kept in a situation where the temperature 
does not rise above its boiling-point, and should be handled with caution, 
as its vapor forms an explosive mixture with air. 

Gasoline, also obtained from naphtha, boils at 76.6° C — 170° F., and 
has a specific gravity of 0.63 — 0. 61 = 80° — 90° Baume, and is used, as its 
name implies, for the manufacture of illuminating gas. 

Benzine, or benzoline, is a colorless liquid, boiling at 148° C.=298° F., 
having a specific gravity of 0.73 = 60° Baume, and a peculiar odor. It is 
largely used in the arts as a solvent for fatty substances. It must not be 
confounded with benzene or benzol, which is a totally different substance, 
obtained from coal-tar (see p. 315). The two substances resemble each 
other in appearance, but maybe distinguished by the following characters: 

Benzoline. , Benzene. 

Boils at about 140° C., sp. gr. 0.69— 0.73, ' Boils at 80° C, sp. gr. 0.88, or 30° 
or 60° to TO" Baume ; does not crystallize ' Baume; crystallizes at 3.2° C. 
at the freezing-point of water. 

Smells of petr leum ; does not sensibly i Smells of coal-tar ; dissolves pitch 



dissolve pitch or absolute carbolic acid in 
the cold. 



readily, forming a dark brown solution. 
Is miscible with absolute carbolic acid in 
j all proportions. 



The most important product of petroleum is that portion which 
passes over at temperatures above 183° C, and which constitutes what 
is usually known as kerosene — various other trade-names being applied to 
it in different degrees of purity, and by different manufacturers. In the 
manufacture of these burning-oils care must be had that the more volatile 
compounds are separated, and that the temperature be not pushed too 
high; in the latter case the oil is "cracked, " i. e., the denser oils remain- 
ing in the still are dissociated, forming highly volatile compounds, which 
mix with the product. In either case the kerosene is liable to give rise 
to accidents, either by igniting, in case the lamp is broken or overturned, 
and, in very bad oils, by forming with air a mixture which may explode 
the lamp. In order to guard against such accidents, laws have gradu- 
ally been framed in various States and countries, regulating the manufac- 
ture, transportation, and storage of these oils. The tests to which they 
are subjected relate to the temperature at which they give off inflamma- 
ble vapors and that at which they ignite. The tests are applied by 
gradually warming the oil, and noting the temperature, indicated by a 
thermometer plunged in it, at the time when a lighted match, carried over 
its surface, produces a flash, and the temperature when the oil itself 
ignites; the former is known as the "flashing-point," the latter as the 
"burning-point;" the former is about 5° — 8° C. = 10° — 15° F. below the 
latter. It was formerly supposed that an oil flashing at 43° C = 110° 
F. was safe ; but subsequent experience has shown that kerosene gives 
off explosive vapors at a temperature 5° — 8° C. = 10° — 15° F. below its 
flash-point, and 14°— 17° C. = 25°— 30° F. below its burning- point, and 
serious accidents have resulted from the use of oils of 110° flash. A 
kerosene is now required, therefor, to have a flash-point of 60° C.= 
140° F., and a burning-point of 65.5C. = 150° F. ; an oil of lower test is 
unsafe. 

If the oil be colored, as is usually the case, it is purified — refine.d — by 
heating with sulphuric acid, and then with caustic soda. The neigh- 
borhood of petroleum refineries, as residents of New York are aware, is 
frequently infected with disgusting and deleterious odors, emanating 



METHYL CHLORIDE. 161 

partly from the waste acid used in the refining, and partly from the va- 
pors issuing from the stills when the oil is purposely " cracked," that a 
greater yield of kerosene may be obtained. 

From the residue remaining after the separation of the kerosene, a 
variety of other products are obtained. Lubricating oils, of too high 
boiling-point for use in lamps. JParaffine, a white, crystalline solid, fusi- 
ble at 45° — 65°, which is used in the arts for a variety of purposes for- 
merly served by wax, such as the manufacture of candles. In the lab- 
oratory it is very useful for coating the glass stoppers of bottles, and 
for other purposes, as it is not affected by acids or by alkalies. It is 
odorless, tasteless, insoluble in water and in cold alcohol ; soluble in boil- 
ing alcohol and in ether, fatty and volatile oils, and mineral oils. It is 
also obtained by the distillation of certain varieties of coal, and is found 
in nature in fossil wax or ozocerite. 

The products known as vaseline, cosmoline, etc., which are now so 
largely used in pharmacy and perfumery, are mixtures of paraffine and 
the heavier petroleum oils. Like petroleum itself, its various commercial 
derivatives are not definite compounds, but mixtures of the hydrocarbons 
of this series. 



CHLORINE, BROMINE, AND IODINE DERIVATIVES OP 
HYDROCARBONS OF THE SERIES C n H 2n+2 . 

By the action of bromine upon the hydrocarbons of this series, or by 
the action of hydrochloric, hydrobromic, or hydriodic acid upon the cor- 
responding hydrate, compounds are obtained in which one atom of hydro- 
gen of the hydrocarbon is replaced by an atom of chlorine, bromine, or 
iodine: 



C 2 H 6 +Br 2 = C,H 5 Br + HBr, 

Ethyl Bromine. Ethyl Hydrobromic 

hydride. bromine. acid. 

C 2 H 5 OH + HC1 = C 2 H 5 C1 + H 2 0, 

Ethyl Hydrochloric Ethyl Water, 

hydrate. acid. chloride. 



These substances are also known as haloid ethers. 



Methyl Chloride— CH.C1, 

Is obtained as a colorless gas, slightly soluble in water, and having a sweet- 
ish odor and taste, by distilling together sulphuric acid, sodium chloride, 
and methylic alcohol; also, on a commercial scale, from the residues of the 
manufacture of beet-sugar. Under the influence of cold it forms a liquid 
which boils at — 22°. 

It is inflammable, and burns with a greenish flame. When mixed with 
chlorine and exposed to sunlight, a further substitution of chlorine for 
hydrogen takes place. When heated with potassium hydrate, it is con- 
verted into methyl hydrate. 
11 



162 GENERAL MEDICAL CHEMISTRY. 



Methyl Bromide— CH 3 Br. 

A colorless liquid; boils at 13°; sp. gr. 1.664; has an ethereal and faintly 
alliaceous odor; prepared by the combined action of phosphorus and bro- 
mine upon methyl hydrate. 



Methyl Iodide— CH 3 I. 

A colorless liquid; boils at about 45°; sp. gr. 2.237; burns with diffi- 
culty, giving off violet vapors of iodine. It is prepared by a process sim- 
ilar to that used for obtaining the bromide. It is used in the laboratory, 
for the introduction of radical methyl into other compounds; and in the 
arts, in the manufacture of aniline colors. 



Ethyl Chloride. 

Hydrochloric or muriatic ether, C 2 H 5 C1. — A colorless, mobile liquid; 
boils at 11°; has an agreeable odor; burns with a greenish flame. It is 
obtained by passing hydrochloric acid gas through ethylic alcohol to satu- 
ration, and distilling over the water-bath. It is used in medicine in alco- 
holic solution ; it also exists in tr. ferri chlorldl. 



Ethyl Bromide. 

Hydrobromic ether, C 2 H,Br. — A colorless liquid; boils at 40.7°; has 
an ethereal odor; a taste at first sweet, afterward disagreeable and burn- 
ing. Obtained by the combined action of phosphorus and bromine on 
ethylic alcohol. Possesses anaesthetic properties. 



Ethyl Iodide. 

Hydriodic ether, C 3 H 6 I. — This compound, which is of considerable 
commercial importance since the introduction of the aniline industry, and 
which has also rendered very valuable service in the laboratory, is pre- 
pared by placing thirty-five parts of absolute alcohol and seven parts of 
phosphorus in a vessel surrounded by a freezing mixture, and gradually 
adding thirty-two parts of iodine; when the action has ceased, the liquid 
is decanted, distilled over the water-bath, and the distillate washed and 
purified. 

It is a colorless liquid; heavier than water; boils at 72.2°; has a power- 
ful ethereal odor, and becomes brown when exposed to the light. It burns 
with difficulty. 

Similarly constituted chlorides, bromides, and iodides of the higher 
radicals of this series have been obtained; they resemble those described 
in their properties and methods of formation. The use of amyl chloride, 
C 6 H n Cl, as an anaesthetic, has been suggested. 



MONOCHLORMETHYL CHLORIDE. 163 



Products of Further Substitution. 

When chlorine is allowed to act upon marsh-gas, it replaces one or 
more atoms of hydrogen, according to the proportions of the two gases 
and the energy of the reaction. If we consider marsh-gas as being the 
hydride of the radical methyl, the first of these products is the simple 
methyl chloride, already mentioned; the second, the chloride of a radical 
obtained from methyl by the substitution of one atom of chlorine for one 
of its atoms of hydrogen, CH 2 C1 2 , etc. The formation of these products 
may be indicated thus: 

CH 4 + C1 2 =HC1 +CH.C1. 
CH 4 + 2C1 2 = 2HC1 + CH 2 C1 2 . 
CH 4 + 3C1 2 = 3HC1 + CHC1 3 . 
CH 4 + 4C1 2 = 4HC1 + CC1 4 . 

Considering them as derivatives of marsh-gas, methyl hydride, they 

CFT ) PIT ) 

should be called: tt 3 [■ = Methyl hydride = marsh-gas. p? [■ —Methyl 

chloride. ' 2 ™ [• = Monochlormethyl chloride. p? j- = Dichlor- 

CC1 ) 
methyl chloride = chloroform. p? >■ = Trichlormethyl chloride = tetra- 

chloride of carbon. 

Similar products are formed with bromine and iodine. 

Monochlormethyl Chloride. 

Methene chloride — Methylene chloride — Dichloromethane — CH„C1,C1. 
— By some chemists considered as the chloride of a divalent radical, 
(0H 2 )" = methylene, whose existence, however, in this compound is prob- 
lematical. 

It is obtained by the action of chlorine upon methyl chloride, or by 
shaking an alcoholic solution of chloroform with powdered zinc and a 
little ammonium hydrate, the nascent hydrogen thus formed separating 
a portion of the chlorine as hydrochloric acid. In either case the product 
must be purified. 

It is a colorless, oily liquid; boils at 40° — 42°; sp. gr., 1.3 G; its odor is 
similar to that of chloroform. It is very slightly soluble in water, and is 
not inflammable. 

Under the names bichloride of methylene and chloromethyl, it has 
been used as a substitute for chloroform in the production of anaesthesia, 
and the hope was entertained that it would prove the safer agent of the 
two — a hope which subsequent experience has not justified. In the three 
years following its introduction (1868-1871) four cases of death from its 
use were recorded. 



164 GENERAL MEDICAL CHEMISTRY. 



Dichlormethyl Chloride. 

Methenyl chloride — Formyl chloride — Chloroform — Chloroformwn 
(U. S., Br.) — CHC1 2 C1. — This important compound was discovered in 1831,. 
by Dr. Samuel Guthrie, of Sackett's Harbor, N. Y., and at about the 
same time by Liebig, in Germany, and by Soubeiran, in France. 

It is obtained by heating to 40°, in a capacious still, thirty-five to 
forty litres of water, adding five kilos of recently slacked lime and ten 
kilos of chloride of lime; two and one-half litres of alcohol are then added, 
and the temperature is quickly raised until the product begins to distil 
over, when the fire is withdrawn, the action continuing of itself until to- 
ward the end, when heat is again applied. By this process the crude 
chloroform of the dispensatory, Chloroformum venale (U. S.), is obtained. 
It is still very impure, and, to purify it, it is first shaken with sulphuric 
acid, from which it is separated by decantation, then thoroughly mixed 
with alcohol and recently ignited potassium carbonate, the mixture 
shaken, and redistilled at the temperature of the water-bath; the distillate 
is pure chloroform. 

Chloroform is a colorless, volatile liquid, having a strong, agreeable 
ethereal odor, and a sweet taste. It is heavier than water (sp. gr. 1.497); 
very sparingly soluble in water; miscible with alcohol and ether in all 
proportions; boils at 60.8°. It ignites with difficulty, but may be burned 
from a cotton wick, giving a red, smoky flame, bordered with green, 
which gives off vapors of lrydrochloric acid. It is a good solvent for 
many substances insoluble in water — phosphorus, iodine, fats, resins, 
caoutchouc, gutta-percha, and the alkaloids. 

Chloroform is not acted on by concentrated sulphuric acid, except by 
long contact, when hydrochloric acid is given off. Chlorine, under the 
influence of direct sunlight, converts it into tetrachloride of carbon, CC1 4 , 
and hydrochloric acid. It is not attacked by the alkalies in aqueous so- 
lution; but when heated with them in alcoholic solution, it is decomposed 
with formation of chloride and formiate of the alkaline metal. If a 
small quantity of aniline be present during the action of the alcoholic 
solution of the alkali upon chloroform, isobenzonitril is formed, and may 
be recognized by its peculiar odor. Perfectly pure chloroform is not 
altered by exposure to light; but if it contain compounds of nitrogen, 
even in ven^ minute quantity (derived from impurities in the sulphuric 
acid used in its purification), it is gradually decomposed, when exposed 
to direct sunlight, into hydrochloric acid, chlorine, and other substances. 

The most notable property of chloroform is its power of producing 
anaesthesia when its vapor, largely diluted with air, is inhaled. If chlo- 
roform be used at all as an anaesthetic, the physician should satisfy him- 
self of its purity before using it. The substances with which it is liable 
to be contaminated are alcohol, aldehyde, hydrochloric acid, and methyl 
compounds. Alcohol may be detected, if present in large quantity, by 
the low specific gravity of the chloroform, by its sinking through water 
in opaque, pearly drops, and by the slow separation and diminution in 
volume of a measured quantity of chloroform when shaken with water. 
If alcohol be present in small quantity, it is revealed by the production of 
a green color when the impure chloroform is shaken with ferrous dinitro- 
sulphide (obtained by acting on ferric chloride with a mixture of potas- 
sium nitrate and ammonium hydrosulphide). Chloroform containing 
aldehyde communicates a brown color to liquor potassas heated with it. 



DICHLORMETHYL CHLORIDE. 165 

Chloroform containing hydrochloric acid reddens blue litmus paper, and 
causes a white precipitate in an aqueous solution of silver nitrate, when 
shaken with it. Probably the most dangerous contaminations of chloro- 
form are certain methylic and empyreumatic compounds, which, if im- 
properly prepared, it contains in small quantities. The absence of these 
is ascertained by : 1st, shaking the chloroform, in a glass-stoppered bot- 
tle, with an equal volume of colorless sulphuric acid. After twenty-four 
hours the chloroform (upper) layer should be perfectly colorless, and the 
acid layer colorless or faintly tinged with yellow; 2d, evaporating a small 
quantity spontaneously, the last portions should have no pungent odor, 
-and the remaining film of moisture should have no odor or taste other 
than those of chloroform. 

Toxicology . — The action of chloroform varies as it is taken by the 
stomach or by inhalation. In the former case, owing to its insolubility, 
but little is absorbed, and the principal action is the local irritation of 
the mucous surfaces. Recovery has followed a dose of four ounces, and 
•death has been caused by one drachm, taken into the stomach. 

Chloroform vapor acts much more energetically, and seems to owe its 
potency for evil to its paralyzing influence upon the nerve-centres, nota- 
bly upon those of the heart. While persons suffering from heart disease 
are particularly susceptible to the paralyzing effect of chloroform vapor, 
there are several cases recorded of death from the inhalation of small 
quantities, properly diluted, in which no heart-lesion was found upon a 
post-mortem examination. 

Chloroform is apparently not altered in the system, and is eliminated 
with the expired air. 

There is no chemical antidote to chloroform. When it has been swal- 
lowed, the stomach-pump and emetics are indicated; when taken by inha- 
lation, a free circulation of air should be established about the face; 
artificial respiration and the application of the induced current to the sides 
of the neck should be resorted to. 

The nature of the poison is usually revealed at the autopsy by its 
peculiar odor, which is most noticeable on opening the cranial and thora- 
cic cavities. In a toxicological analysis, chloroform is to be sought for 
especially in the lungs and blood. These are placed in a flask, if acid, 
neutralized with sodium carbonate, and subjected to distillation at the 
temperature of the water-bath. The vapors are passed through a tube of 
difficultly fusible glass; at first the tube is heated to redness for about an 
inch of its length, and a piece of filter-paper, moistened with starch paste 
and with a solution of potassium iodide, is held at the orifice; if chloro- 
form vapor be present, it is decomposed into carbon, hydrochloric acid, 
;and free chlorine, and the last-named turns the paper blue by the libera- 
tion of iodine (the color is afterward bleached if chlorine be present in 
large quantity). The escaping vapor is then allowed to bubble through 
a solution of silver nitrate acidulated with nitric acid, when, if chloroform 
be present, a white precipitate, soluble in ammonia, is formed. Finally, 
the tube is allowed to cool, and the distillate collected in a pointed tube; 
if chloroform be present in considerable quantities it collects in a distinct 
layer or in drops at the lower, pointed end of the receiver. The superna- 
tant, watery liquid is drawn off with a pipette; the drops of chloroform, 
whose odor may be recognized, dissolved in a small quantity of alcohol, 
and to this solution a little alcoholic solution of potassium hydrate and 
two or three drops of aniline are added, and the mixture gently warmed; 
if chloroform be present, even in small quantity (one part to five thou- 



166 GENERAL MEDICAL CHEMISTRY. 

sand parts alcohol) the peculiar, disagreeable odor of isobenzonitril is ob~ 
served (Hofmann). 

Tetrachloride of Carbon, CC1 4 — the product of the most com- 
plete substitution of chlorine for hydrogen in marsh-gas. It is formed by 
the prolonged action of chlorine upon methyl chloride, or upon chloroform, 
under the influence of direct sunlight. More quickly by passing chlorine, 
charged with vapor of carbon disulphide, through a red-hot tube, and 
purifying the product. 

It is a colorless, oily liquid, insoluble in water, soluble in alcohol and 
in ether; having an agreeable ethereal odor ; sp. gr. 1.56; boiling at 78°. 
Its vapor, when heated to redness, either alone or mixed with hydrogen,, 
is decomposed, yielding a mixture of dichloride, C Q C1 4 , trichloride, C„C1 , 
and free chlorine. 

Its action upon the economy is similar to that of chloroform. It is 
known in pharmacy as chlorocarbon. 



Dibromomethyl Bromide. 

Methenyl bromide — Formyl bromide — JBromoform — CHBr 2 , Br. — is 
prepared by gradually adding bromine to a cold solution of potassium 
hydrate, until the liquid begins to be colored, and rectifying over calcium 
chloride. 

A colorless liquid of sp. gr. 2.13, having an aromatic odor and a sweet 
taste, less volatile than chloroform, boils at 150° — 152°, solidifies at —9°, 
sparingly soluble in water, to which it communicates its taste and odor,, 
soluble in alcohol and ether. When boiled with alcoholic potash, it 
undergoes a decomposition similar to that of chloroform. It burns with 
difficulty, and is decomposed at a red heat. 

Its physiological action is similar to that of chloroform. It often 
exists as an impurity in commercial bromine, accompanied by carbon 
tetrabromide, CBr 4 . 



Diiodomethyl Iodide. 

Methenyl iodide — Formyl iodide — Iodoform — CHI 2 I. — Formed, like 
chloroform and bromoform, by the combined action of potash and the 
halogen upon alcohol; it is also produced by the action of iodine upon a 
great number of organic substances, and is usually prepared by heating 
to 60° — 80° a mixture of three parts alkaline carbonate, ten parts water, 
one part iodine and one part ethylic alcohol, and purifying the product 
by recrystallization from alcohol. 

Iodoform differs widely from its chlorine and bromine congeners both 
in appearance and properties. It is a solid, crystallizing in yellow hexa- 
gonal plates, which melt at 115° — 120°. It may be sublimed, a portion 
being decomposed. It is insoluble in water, acids, and alkaline solutions; 
soluble in alcohol, ether, carbon disulphide, and the fatty and essential 
oils; the solutions, when exposed to the light, undergo decomposition 
and assume a violet-red color. It has a sweet taste and a peculiar, pene- 
trating odor, resembling, when the vapor is largely diluted with air, that 
of saffron. When heated with potash, a portion is decomposed into 
formiate and iodide, while another portion is carried off unaltered witri 
the aqueous vapor. It contains 96.7$ of its weight of iodine. 



MOISTO ATOMIC ALCOHOLS. 167 

It possesses ansesthetic powers, less active than those of chloroform 
and bromoform, and principally localized to the sphincters. Experiments 
upon animals show that it is poisonous in smaller doses than iodine. 



Diehlormethyl Iodide. 

Chloroiodoform, CHC1 2 ,I — is formed when iodoform is heated with 
mercuric chloride; a dark red liquid distils, which, when treated with 
potash and redistilled, yields a yellowish liquid, having an aromatic odor 
and a sweetish taste; sp. gr. 1.96. 



Dibromomethyl Iodide. 

JBromoiodoform, CHBr 2 I — is a colorless liquid, solidifying at 0°, very 
volatile, sweet in taste, having a penetrating odor; obtained by the 
action of bromine upon iodoform. 



Chlorinated Derivatives of Ethyl Chloride. 

By the action of chlorine upon ethyl chloride, a progressive substitu- 
tion of atoms of chlorine for atoms of hydrogen occurs, with formation of 
the following substances : 



o 



Monochlorethyl chloride C 2 H 4 C1,C1 boils at 64 

Dichlorethyl chloride C 2 H 3 C1 2 ,C1 .... boils at 75 

Trichlorethyl chloride C,H 9 C1„C1. . . .boils at 102° 

Tetrachlorethyl chloride C 2 HC1 4 ,C1 . . . .boils at 146° 

Carbon trichloride C 2 C1 6 boils at 182° 

The first of these is isomeric with " Dutch liquid " (see page 229) and 
possesses anaesthetic powers. A product containing the three following, 
in varying quantities, has been used as an anaesthetic under the names 
aether anoestheticits Arani. Carbon trichloride, also called sesquichloride 
or perchloride of carbon, is obtained by the action of chlorine upon ethyl 
chloride or upon Dutch liquid, under the influence of sunlight. It forms 
colorless, transparent crystals, almost tasteless, having an odor resembling 
that of camphor; hard, insoluble in water, soluble in alcohol and in ether, 
fusing at 160°, volatile at 182°. Has been used medicinally as a local 
anaesthetic, and in cholera. 



MONOATOMIC ALCOHOLS. 

Series CJEI 2n+2 0. 

This series consists of the hydrates of the radicals C 7l H 2n +1 , derived 
from the saturated hydrocarbons (see pp. 149, 157), and contains some of 
the most important of the organic compounds. The following is a list of 
the terms of the series which have been studied, and their prominent 
physical properties. 



168 



GENERAL MEDICAL CHEMISTRY. 



Alcohols — Series CJH 2n+2 0. 



Name. 



Empirical 
formula. 



Methyl hydrate CH 4 

Ethyl hydrate . . . 

Propyl hydrate C 3 H 8 

Butyl hydrate dHn.O 

Amyl hydrate C5H12O 

Hexyl hydrate C 6 H 14 



Heptyl hydrate. 
Octyl hydrate . . 
Nonyl hydrate . 
Decyl hydrate . . 
Cetyl hydrate . . 
Ceryl hydrate . . 
Myricyl hydrate. 



C 7 H 16 

CsHjeO 
C.IH20O 

Ci H 2 yO 
Cj C H 3 40 
Cj7H 56 

C30HG2O 



Typical 
formula. 



CH 3 ) 
CyHft 

C3H7 

H 



O 



CiHg 



1° 



o 



^sHji / ft 

Hf° 

CeHi3 ) ft 

Hf° 

C7H16 ) ft 

CeHi7 ) f. 

Hf u 
C9H19 ) f>. 

^loH21 f ft 

Hf° 

C16H33 / ft 
Hp 

C27H5 
H 

C30HB1 
H 



I 



Fusing- 
point. 



20° 



49 c 
79 ( 

85' 



Boiling- 
point. 



66°.5 

78°.3 
96°.7 

114°. 7 

132° 

150° 

168° 

186° 

204° 



Specific 
gravity. 



0.814 
0.8095 
0.820 
0.817 

0.820 



Methyl Hydrate. 

Methylic alcohol — Carbinol — Pyroxylic spirit — Wood spirit — CH 3 HO. 
■ — Does not exist in nature, may be obtained from marsh-gas, methyl 
hydride, by first converting it into the iodide, which is then acted upon 
by potassium hydrate: 

CH 3 I + KHO = KI + CH 3 HO. 

It is obtained in the arts by the destructive distillation of wood (whence 
the name, from /jlzOv, wine, and v\rj, wood). When wood is decomposed at 
a high temperature in closed vessels, there are formed charcoal, gaseous 
and tarry products, and an aqueous fluid which is known as crude wood 
vinegar, and contains a number of substances, notably acetic acid and 
methylic alcohol. The crude vinegar is separated by decantation from 
the tarry products and redistilled, the first tenth is collected, treated with 
quicklime and again distilled ; the distillate treated with dilute sulphuric 
acid, decanted, and again distilled from quicklime ; the product, still quite 
impure, is the wood alcohol, wood naphtha, and pyroxylic spirit of com- 
merce. It may be further purified by causing it to combine with calcium 
chloride, decomposing the crystalline compound formed by the addition 
of water, and rectifying from quicklime; all these distillations are carried 



ETHYL HYDRATE. 169 

on at the temperature of the water-bath. The pure hydrate is obtained 
by forming a crystalline compound, such as methyl oxalate, which is 
purified, decomposed, and the product rectified until the boiling-point is 
constant at 66.5°. 

Pure methyl alcohol is a colorless liquid, having an ethereal and alco- 
holic odor, and a sharp, burning taste; sp. gr. 0.814 at 0°; boils at 66.5°, 
bumping so as to render its distillation difficult. It burns with a pale 
flame, giving less heat than that of ethylic alcohol. It mixes with water, 
alcohol, and ether in all proportions; is a good solvent of resinous sub- 
stances, and also dissolves sulphur, phosphorus, potash, and soda, the 
solutions of the last-named substances becomino- colored on contact with 
air. 

Methyl hydrate is not affected by exposure to air under ordinary cir- 
cumstances, but in the presence of platinum-black it is oxidized, with for- 
mation of the corresponding aldehyde and acid, formic acid. 

Nitric acid, aided by heat, decomposes it with formation of nitrous 
fumes, formic acid, and methyl nitrate. When heated with nitric acid and 
silver nitrate, it produces no fulminate. Sulphuric acid acts upon methyl 
alcohol as it does upon ethyl hydrate (a.v.). The organic acids pro- 
duce ethers with methyl alcohol, as they do with all the members of the 
series. 

It dissolves potassium and sodium with liberation of hydrogen, and 

OFT ) 
the formation of oxides of methyl and potassium or sodium; ^ [O or 

^r 3 y O. With baryta and with calcium chloride it forms crystallized 

compounds. With hydrochloric acid, under the influence of the galvanic 
current, it forms an oily substance having the composition C 2 H 3 C10. 

Uses. — It is used in the arts in the preparation of varnishes; as a 
solvent in many processes, and in the manufacture of aniline dyes. 

Methylated spirit is ethyl alcohol containing sufficient wood spirit to 
render it unfit for the manufacture of ardent spirits by reason of the dis- 
gusting odor and taste which crude wood alcohol owes to certain empy- 
reumatic products which it contains. Spirits so treated are not subject 
to the heavy duties imposed upon ordinary alcohol, and are, therefor, 
largely used in the arts and for the preservation of anatomical prepara- 
tions; it contains one-ninth of its bulk of wood naphtha. 

When taken internally it produces the same effects as does ordinary 
alcohol; it seems, however, to be rather more active. Its use as a thera- 
peutic agent has been suggested. 



Ethyl Hydrate. 

Ethylic alcohol — Methyl carbinol — Vinic alcohol — Alcohol — Spirits 
of wine — C 2 H 5 HO. — Liquids containing alcohol were known and were 
prepared for use as beverages in remote antiquity. It was only in the 
middle ages, however, that the alchemists separated alcohol, still con- 
taining water, from wine, whence it received the name, still used in speak- 
ing of diluted alcohol, of spirits of wine. Saussure was the first to de- 
termine its composition. 

Alcohol does not exist in nature, but is produced in a number of re- 
actions. One method of its formation, which has an historical interest as 



170 GENERAL MEDICAL CHEMISTRY. 

that by which its constitution was determined, is by the formation of sul- 
phovinic acid and the subsequent decomposition of this by water: 

SOJEL+CLH =S0 4 HC a H E 

4 2 2 4 4 2 ;> 

Sulphuric Ethylene Sulphovinic 

acid. acid. 

S0 4 HC 9 H 5 + H a O = S0 4 H 9 + C a H 6 OH 

Sulphovinic Water. Sulphuric Alcohol, 

acid. acid. 

The sources from which alcohol and alcoholic liquids are industrially 
obtained are always vegetable substances, rich in starch or in glucose, by 
far the greater proportion being obtained from starchy materials. 

The manufacture of alcohol from this source consists of three distinct 
processes: 1st, the conversion of starch into sugar; 2d, the fermentation 
of the saccharine liquid; 3d, the separation, by distillation, of the alcohol 
formed by fermentation. 

The raw materials for the first process are malt and some substance 
(grain, potatoes, rice, corn, etc.) containing starch. Malt is barley which 
has been allowed to germinate, and, at the proper stage of germination, 
roasted. During this growth there is developed in the barley a peculiar 
nitrogenous principle called diastase. The starchy material is mixed 
with a suitable quantity of malt and water, and the mass maintained at a 
temperature of 65° — 70° for two to three hours, during which the dias- 
tase rapidly converts the starch into dextrine, and this in turn into glu- 
cose. The saccharine fluid, or wort, obtained in the first process, is drawn 
off, cooled, and yeast is added. As a result of the growth of the yeast- 
plant, a complicated series of chemical changes take place, the principal 
one of which is the splitting up of the glucose into carbon dioxide and 
alcohol: 

C,H I9 O e =2C,H B OH+3CO, 

Glucose. Alcohol. Carbon 

dioxide. 

There are formed at the same time small quantities of glycerine, succinic- 
acid, and propyl, butyl, and anryl alcohols. 

An aqueous fluid is thus obtained which contains from three to fifteen 
per cent, of alcohol; this is then separated by the third process, that of 
distillation or rectification. The apparatus used for this purpose has been 
so far perfected that by a single distillation an alcohol of 90 — 95 per cent, 
can be obtained. 

In some cases alcohol is prepared from fluids rich in glucose, such as 
grape-juice, molasses, syrup, etc. ; in such cases the first process becomes 
unnecessarv. 

Commercial alcohol always contains water, and when pure or absolute 
alcohol is required, the commercial product must be mixed with some hy- 
groscopic solid substance, such as quicklime, from which it is distilled 
after having remained in contact twenty-four hours. 

Alcohol is a thin, colorless, transparent liquid, having a spirituous odor, 
and a sharp, burning taste; sp. gr. 0.8095 at 0°, 0.7939 at 15°; it boils at 
78.5°, and has not been solidified; at temperatures below —90° it is vis- 
cous. It mixes with water in all proportions, the union being attended by 
elevation in temperature and contraction in volume (after cooling to the 
original temperature). If 52.3 volumes of alcohol be mixed with 47.07 
of water, at 15°, the mixture occupies 96.35 volumes, the maximum of 



ETHYL HYDRATE. 171 

contraction. It also attracts moisture from the air to such a decree that 
absolute alcohol only remains such for a very short time after its prepara- 
tion. It is to this power of attracting water that alcohol owes its preserv- 
ative power for animal substances, and probably also its power of coagula- 
ting albuminoid substances. It is a very useful solvent, dissolving a number 
of gases, most of the mineral and organic acids and alkalies, most of the 
chlorides and carbonates, some of the nitrates, all the sulphates, essences, 
and resins. Most of the varnishes consist of alcoholic solutions of resi- 
nous materials. Alcoholic solutions of fixed medicinal substances are 
called tinctures; those of volatile principles, spirits. 

The action of oxygen upon alcohol varies according to the conditions. 
Under the influence of energetic oxidants, such as chromic acid, or, when 
alcohol is burned in the air, the oxidation is rapid and complete, and is at- 
tended by the extrication of much heat and the formation of carbon di- 
oxide and water: 

C 2 H 6 + 30 2 =2C0 2 + 3H 2 0. 

Mixtures of air and vapor of alcohol explode upon contact with flame. If 
a less active oxidant be used, such as platinum-black, or by the action of 
atmospheric oxygen at low temperatures, a simple oxidation of the alco- 
holic radical takes place, with formation of acetic acid: 

a reaction which is utilized in the manufacture of acetic acid and vineo-ar.- 
If the oxidation be still further limited, aldehyde is formed: 

2C 2 H 6 + 2 = 2C 2 H 4 + 2H 2 0. 

If vapor of alcohol be passed through a tube filled with platinum sponge 
and heated to redness, or if a coil of heated platinum wire be introduced 
into an atmosphere of alcohol vapor, the products of oxidation are quite 
numerous; among them are water, ethylene, aldehyde, acetylene, carbon 
monoxide, and acetal. Heated platinum wire introduced into vapor of 
alcohol continues to glow hj the heat resulting- from the oxidation, a fact 
which has been utilized in Doebereiner's nameless lamp, and in the ther- 
mocautery recently introduced in surgical practice. 

Chlorine and bromine act energetically upon alcohol, producing a 
number of chlorinated and brominated derivatives, the final products be- 
ing chloral and bromal (q. v.). If the action of chlorine be moderated, 
aldehyde and hydrochloric acid are first produced. Iodine acts quite 
slowly in the cold, but old solutions of iodine in alcohol (tr. iodine) are 
found to contain hydriodic acid, ethyl iodide, and other imperfectly 
studied products. In the presence of an alkali, iodine acts upon alcohol 
to produce iodoform. 

Potassium and sodium dissolve in alcohol with evolution of hydrogen; 
upon cooling, a white solid crystallizes, which is the double oxide of ethyl, 
and the alkaline metal: 

Water or hydrogen Potassium hydrate Ethyl hydrate or ox- Oxide of ethyl and 
oxide. or oxide of hydro- ide of hydrogen potassium, 

gen and potassium. and ethyl. 



172 GENERAL MEDICAL CHEMISTRY. 

These compounds, on contact with water, are decomposed, with re- 
generation of alcohol and formation of the alkaline hydrate. 

Nitric acid, aided by a gentle heat, acts violently upon alcohol, pro- 
ducing nitrous ether, brown fumes, and products of oxidation. For the 
action of other acids upon alcohol see the corresponding ethers. 

The hydrates of the alkaline metals dissolve in alcohol, but react up- 
on it slowly; the solution turns brown and contains an acetate. 

If alcohol be gently heated with nitric acid and the nitrate of silver or 
-of mercury, a gray precipitate falls, which is silver or mercury fulminate. 

Uses. — Alcohol is used in a great number of processes, in the arts, 
and in pharmacy, principally as a solvent, but also as a starting-point in 
the manufacture of a number of substances, as vinegar, chloral, chloro- 
form, and ether; as a menstruum in the preparation of tinctures and 
spirits; and to a certain extent as a fuel, when a hot and smokeless flame 
is desired. 

It occurs in commerce, and is used pharmaceutically in different de- 
grees of concentration. 

Absolute alcohol is pure alcohol, C 2 H 6 0, prepared as desired by the 
method given above. It is not purchasable; the so-called absolute alco- 
hol of the shops is rarely stronger than ninety-eight per cent.- 

Alcohol fortius (U. S.) — stronger alcohol, is of sp. gr. 0.817, and con- 
tains ninet}r-two per cent, alcohol. 

Alcohol (U. S.) — sp. gr. 0.835 = Spiritus rectificatus (Br.) — sp. gr. 
0.838 — is the ordinary rectified spirit, used for most purposes in the arts; 
it contains eighty-five per cent, alcohol. 

Alcohol dilutum (U. S.) — sp. gr. 0.941= Spiritus tenuior (Br.) — sp. 
_gr. 0.920 — used for the preparation of tinctures. It contains thirty-nine 
per cent., U. S., or forty-nine per cent., Br., of alcohol. The British 
officinal is of the same strength as the proof spirit of commerce. 

Physiological action. — In a concentrated form, alcohol exerts a de- 
hydrating action upon animal tissues with which it comes in contact; 
•causing coagulation of the albuminoid constituents. When diluted, 
ethylic alcohol may be a food, a medicine, or a poison, according to the 
dose and the condition of the person taking it, When taken in excessive 
doses, or in large doses for a long time, it produces the symptoms and 
lesions characteristic of pure alcoholism, acute or chronic, modified or 
aggravated by those produced by other substances, such as amyl alcohol, 
which accompany it in the alcoholic fluids used as beverages. Taken in 
moderate quantities, with food, it aids digestion and produces a sense of 
comfort and exhilaration. As a medicine it is the most valuable of 
stimulants. 

Much has been written concerning the value of alcohol as a food. If 
it have any value as such, it is as a producer of heat and force by its ox- 
idation in the body; experiments made in the interest of teetotalism have 
failed to show that more than a small percentage (sixteen per cent, in 
twenty-four hours) of medium doses of alcohol ingested are eliminated by 
all channels; the remainder, therefor, disappears in the body, as the idea 
that it can there " accumulate " is entirely untenable. That some part 
should be eliminated unchanged is to be expected from the rapid diffusion 
and the high volatility of alcohol. 

On the other hand, if alcohol be oxidized in the body, we should ex- 
pect, in the absence of violent muscular exercise, an increase in tempera- 
ture, and the appearance in the excreta of some product of oxidation of 
alcohol, aldehyde, acetic acid, carbon dioxide, or water, while the elimi- 



ETHYL HYDRATE. 173- 

nation of nitrogenous excreta, urea, etc., would remain unaltered or be- 
diminished. While there is no doubt that excessive doses of alcohol pro- 
duce a diminution of body temperature, the experimental evidence con- 
cerning" the action in this direction of moderate doses is conflicting- and 
incomplete. 

Of the products of oxidation, aldehyde has not been detected in the- 
excreta, and acetic acid only in the intestinal canal. The elimination of 
carbonic acid, as such, does not seem to be increased, although positive- 
information upon this point is wanting. If acetic acid be produced, this 
would form an acetate, which in turn would be oxidized to a carbonate, 
and eliminated as such by the urine. The elimination of water under the 
influence of large doses of alcohol is greater than at other times, but 
whether this water is produced by the oxidation of the hydrogen of the 
alcohol, or is removed from the tissues by its dehydrating action, is an 
open question. 

While physiological experiment yields only uncertain evidence, the^ 
experience of arctic travellers and others shows that the use of alcohol 
tends to diminish rather than increase the capacity to withstand cold. 
The experience of athletes and of military commanders is that intense- 
and prolonged muscular exertion can be best performed without the use 
of alcohol. The experience of most literary men is that long-continued 
mental activity is more difficult with than without alcohol. 

In cases of acute poisoning by alcohol, the stomach-pump and catheter 
should be used as early as possible. A plentiful supply of air, the cold- 
douche, and strong coffee are indicated. 

Analysis. — The presence of alcohol may be detected by the following- 
reactions, none of which, taken alone, is, however, characteristic of alcohol 
under all circumstances. 

First. — If a solution containing alcohol be heated with a small quan- 
tity of solution of potassium dichromate and sulphuric acid, the liquid 
assumes an emerald green color, and, if the quantity of alcohol be not 
too small, the peculiar fruity odor of aldehyde is observed. The green, 
color is produced under like circumstances by many reducing agents. 

Second. — If an alcoholic liquid be warmed and treated with a few 
drops of potassium hydrate solution and a small quantity of iodine, a yel- 
low, crystalline precipitate of iodoform is produced, either immediately 
or after a time. Many other organic substances produce iodoform under 
similar conditions. 

Third. — If nitric acid be added to a liquid containing alcohol, nitrous 
ether, recognizable by its odor, is given off ; if a solution of mercurous 
nitrate with excess of acid be then added, and the mixture heated, a 
further evolution of nitrous ether occurs, and a yellowish-gray deposit of 
fulminating mercury is formed, which may be collected, washed, dried, 
and exploded. This reaction is well adapted to detecting ethylic in me- 
thylic alcohol, as the latter does not form a fulminate. 

Fourth. — Alcohol may be detected in chloroform by shaking it with 
a fragment of dry potassium hydrate, removing the potash, and shaking 
the chloroform with an equal volume of solution of cupric sulphate; a 
blue precipitate is formed if the chloroform contained alcohol. 

Fifth. — If an alcoholic liquid be heated for a few moments with sulphuric 
acid, diluted with water and distilled, the distillate, on treatment with sul- 
phuric acid and potassium permanganate, and afterward with sodium 
hyposulphite, yields aldehyde, which may be recognized by the produc- 
tion of a violet color on the addition of a dilute solution of f uchsine. 



174 



GENERAL MEDICAL CHEMISTRY. 



The quantity of alcohol in an alcoholic liquid is usually determined by 
observing the specific gravity. If the liquid contain a large quantity of 
alcohol and little or no solid matter, as in the case of the alcohols of com- 
merce, this is done directly; if, however, the liquid hold solid matters in 
solution, as in the case of wines and spirits containing sugar, a measured 
volume of the liquid is distilled until the alcohol is all driven into the dis- 
tillate, whose specific gravity is then determined. The following table 
indicates the percentage of alcohol in mixtures of water and alcohol of 
different specific gravity, at 60° F. = 15.5° C: 



Alcohol 


Specific 


Alcohol 


Specific 


Alcohol 


Specific 


Alcohol 


Specific 


per cent. 


gravity. 


per cent. 


gravity. 


per cent. 


gravity. 


per cent. 


gravity. 





1.0000 


25 


0.9652 


51 


0.9160 


76 


0.8581 


0.5 


9991 


26 


9638 


52 


9135 


77 


8557 


1 


9981 


27 


9623 


53 


9113 


78 


8533 


2 


9965 


28 


9609 


54 


9090 


79 


8508 


3 


9947 


29 


9593 


55 


9069 


80 


8483 


4 


9930 


30 


9578 


56 


9047 


81 


8459 


5 


9914 


31 


9560 


57 


9025 


82 


8434 


6 


9898 


32 


9544 


58 


9001 


83 


8408 


7 


9884 


33 


9528 


59 


8979 


84 


8382 


8 


9869 


34 


9511 


60 


8956 


85 


8357 


9 


9855 


35 


9490 


61 


8932 


86 


8331 


10 


9841 


36 


9470 


62 


8908 


87 


8305 


11 


9828 


37 


9452 


63 


8886 


88 


8279 


12 


9815 


38 


9434 


64 


8863 


89 


8254 


13 


9802 


39 


9416 


65 


8840 


90 


8228 


14 


9789 


40 


9396 


66 


8816 


91 


8199 


15 


9778 


41 


9376 


67 


8793 


92 


8172 


16 


9766 


42 


9356 


68 


8769 


93 


8145 


17 


9753 


43 


9335 


69 


8745 


94 


8118 


18 


9741 


44 


9314 


70 


8721 


95 


8089 


19 


9728 


45 


9292 


71 


8696 


96 


8061 


20 


9716 


46 


9270 


72 


8672 


97 


8031 


21 


9704 


47 


9249 


73 


8649 


98 


8001 


22 


9691 


48 


9228 


74 


8625 


99 


7969 


23 


9678 


49 


9206 


75 


8603 


100 


7938 


24 


9665 


50 


9184 











Alcoholic Beverages. 

The variety of beverages in whose preparation alcoholic fermentation 
plays an important part is very great, and the products differ from each 
other materially in their composition and in their physiological action. 
They may be divided into four classes, the classification being based upon 
the sources from which they are obtained and upon the method of their 
preparation. 

I. — Those prepared by the fermentation of malted grain — beers, ales t 
and porters. 

II. — Those prepared by the fermentation of grape-juice — wines. 

III. — Those prepared by the fermentation of the juices of fruits other 
than the grape — eider, fruit-wines. 

IV. — Those prepared by the distillation of some fermented saccharine 
liquid — ardent spirits. 



ALCOHOLIC BEVERAGES. 175 

" JBeer, ale, and porter are aqueous infusions or decoctions of malted 
grain (occasionally of rice, maize, or potatoes), fermented and flavored 
with hops; they contain, therefor, the soluble constituents of the grain 
employed; dextrine and glucose, jDroduced during the malting; alcohol 
and carbon dioxide produced during the fermentation; and the soluble 
constituents of the flavoring material. Their color, which varies from pale 
amber to dark brown, depends upon the proportion of malt, dried at a high 
temperature, used in their preparation. 

The alcoholic strength of malt liquors varies from 1.5 to 9 per cent. 
"Weiss bier contains 1.5 — 1.9 per cent. ; lager, 4.1 — 4.5 per cent. ; bock bier, 
3.88 — 5.23 per cent.; London porter, 5.4 — 6.9 per cent.; Burton ale, 5.9 per 
cent. ; Scotch ale, 8.5 — 9 per cent. Malt liquors all contain a considerable 
quantity of nitrogenous material (0.4 — 1 percent. N.), and succinic, lactic, 
and acetic acids. The amount of inorganic material, in which the phos- 
phates of potassium, sodium, and magnesium predominate largely, varies 
from 0.2 to 0.3 per cent. The amount of water varies from 79.66 in Bur- 
ton ale, to 91.8 in weiss bier. The specific gravity from 1.014 to 1.033. 

The adulterations of malt liquors are numerous and varied. Water 
is added to increase bulk; it may be detected by the taste, and by the 
low specific gravity of the beer deprived of its alcohol. Sodium carbonate 
is frequently added with the double purpose of neutralizing an excess of 
acetic acid and increasing the foam. The most serious adulteration of 
beer consists, however, in the introduction of bitter principles other than 
hops, and notably of strychnine, cocculus indicus (picrotoxin), and picric 
acid. Of late years artificial glucose (made from starch by the action of 
dilute sulphuric acid) has been used by some brewers; a substitution 
which would be perfectly justifiable and harmless, were it not for the fact 
that glucose prepared in this way is frequently, if not always, contami- 
nated with arsenic, which it derives from the acid used in its manufacture. 
Wines have been in use from remote antiquity, and are prepared in 
infinite variety in almost all temperate countries. 

The grapes are collected with more or less care, and in different 
•degrees of ripeness; for the finest grades each berry is separately plucked 
as it reaches the proper degree of ripeness; for the commonest ripe, un- 
ripe, and damaged grapes are thrown into the press indiscriminately. In 
the manufacture of most red wines and of champagnes, the grape is not 
allowed to reach full maturity. The grapes are expressed, and the juice, 
together with the skins and seeds, or marc, is placed in a butt with a 
perforated bottom, through which it is allowed to trickle into the fer- 
mentation vats; in the case of red wines the marc is allowed to remain in 
contact with the must, or juice, during a part at least of the fermentation, 
in order that the alcohol developed may take up a proper quantity of 
coloring matter; in the case of white wines, contact with a small quantity 
of the stalks is necessary to avoid stringiness. The fermentation of the 
must, which takes place without the addition of yeast, requires about 
fourteen days, at the end of which the wine is drawn off from the lees 
into barrels, in which it is kept at a low temperature, and protected from 
the air as far as possible, to avoid the establisment of acetic fermentation. 
If the must be rich in glucose and poor in nitrogenized material, and if 
the fermentation be arrested before the glucose has been entirelv con- 
verted into alcohol, a sweet wine is obtained; under the contrary con- 
ditions a dry wine is the result. During the fermentation, as the per- 
centage of alcohol increases, acid potassium tartrate is deposited, being 
insoluble in alcoholic liquids. Tartaric acid is the predominating acid in 



176 GENERAL MEDICAL CHEMISTRY. 

the grape; while in other fruits malic and citric acids, whose acid salts 
are soluble in alcoholic liquids, exist in greater proportions; hence, the 
fermented drinks prepared from fruit other than grapes are sharp and 
thin in taste. 

Most wines of good quality improve in flavor with age, and this im- 
provement is greatly hastened by the process of pasteuring, which con- 
sists simply in warming the wine to a temperature of 60° C, without 
contact of air. 

Wines grown in different districts, and from different kinds of grapes, 
differ greatly in their appearance, flavor, color, and alcoholic strength; 
they may be divided into two classes — light and heavy wines. 

Light wines are those whose percentage of alcohol is less than 
twelve per cent. In this class are included the red and white French and 
German wines, clarets, Sauternes, Rhine, and Moselle wines; champagnes, 
Burgundies, the American wines, except some varieties of California 
wine, Australian, Greek, Hungarian, and Italian wines. 

The champagnes and some Moselle wines are sparkling, a quality 
which is communicated to them by bottling them before the fermentation 
is completed, thus retaining the carbon dioxide, which is dissolved by 
virtue of the pressure which it exerts. They are dry and sweet in pro- 
portion as the sugar is completely or partially consumed during the fer- 
mentation. When properly prepared they are agreeable to the palate,, 
and assist the digestion; when new, however, they are liable to com- 
municate their fermentation to the contents of the stomach and thus seri- 
ously disturb digestion. 

Of the still wines, the most widely used are the clarets, or red Bor- 
deaux wines, and the hocks, or white Rhine and Moselle wines. The 
former are of low alcoholic strength, mildly astringent, and contain but a 
small quantity of nitrogenous material, qualities which render them par- 
ticularly adapted to table use and as mild stimulants, especially for those 
predisposed to gout. The Rhine wines are thinner and more acid, and 
generally of lower alcoholic strength than the clarets. The Burgundy 
and Rhone wines are celebrated for their high flavor and body; they are 
not strongly alcoholic, but contain a large quantity of nitrogenous ma- 
terial, to which they are indebted for their notoriety as developers of 
gout. 

Our native American wines, particularly those of the Ohio valley and 
of California, are yearly improving in flavor and quality; they more closely 
resemble the Rhine wines and Sauternes than other European wines. 

Heavy wines are those whose alcoholic strength is greater than twelve 
per cent, usually fourteen to seventeen per cent; they include the sherries, 
ports, Madeiras, Marsala, and some California wines, and are all the pro- 
ducts of warm climates. 

Sherry is an amber-colored wine, grown in the south of Spain, and 
officinal under the name of Vinwn Xericum (U. S., Br.). Marsala closely 
resembles sherry in appearance, and is frequently substituted for it. 
Port, officinal as ~Vinum portense (U. S.), is a rich, dark red wine, grown 
in Portugal. 

The adulteration of wine by the addition of foreign substances 
is confined almost entirely to their artificial coloration, which is pro- 
duced by the most various substances, indigo, logwood, fuchsine, etc. 
(see Bull. d. 1. Soc. Chim. xxv., 435, 483, 530). The addition of natural 
constituents of wines, obtained from other sources, and the mixing of 
different grades of wine are, however, extensively practised. Water and 



ALCOHOLIC BEVEBAGES. 



177 



alcohol are the chief substances so added; an excess of the former may be 
detected by the taste, and the low specific gravity after expulsion of the 
alcohol. Most wines intended for export are fortified by the addition of 
alcohol; when the alcoholic spirit used is free from amyl alcohol, and is 
added in moderate quantities, there can be no serious objection to the 
practice, especially when applied to certain wines which, without such 
treatment, do not bear transportation. The mixing of fine grades of wine 
with those of a poorer quality is extensively practised, particularly with 
champagnes, clarets, and burgundies, and is perfectly legitimate. The 
same cannot be said, however, of the manufacture of factitious wine, 
either entirely from materials not produced from the grape, or by con- 
verting white into red wines, or by mixing wines with coloring matters, 
alcohol, etc., to produce imitations of wines of a different class, an indus- 
try which flourishes extensively in Normandy, at Bingen on the Rhine, 
and at Hamburg. The wines so produced are usually heavy wines, port 
and sherry, so-called. 

In the following table are given, in percentages by weight, the chief 
constituents of the more generally used varieties of wine: 





>> 

'> 

i 

fco 
o 
S 

*s 

o 
P, 

02 


+3 

.S 3 
"55 
is 
>» 

Si 

"o 
.a 
o 


u 
"3 

o 


1 

d 


<5 

43 

GO 

d 

Id 

n u 

SB 



H 


u 
at 
be 
3 
00 

a 
P. 

S3 

u 




m 

V 



ss 

u 


■si 

CO 

< 


c 
"a 

a 
E-i 


Claret 


999.8 

992.2 

992.2 

992.2 

993.5 

992,5 

991.6 

992.9 

938.0 

996.0 

1001.3 

999.5 

992.2 

1057.0 

1038.0 

1038.0 

1038.0 


10.44 

10.84 

10.73 

7.77 

9.98 

10.81 

10.23 

17.89 

16.98 

16.48 

16.12 

16.38 

12.08 

12.04 

12.04 

9.53 

9.61 


.374 
.435 
.435 
.435 
.440 
.386 
.419 
.390 
.379 
.257 
.528 
.241 
.556 
.556 
.556 
.556 
.556 


.137 
.169 
.169 
.169 
.217 
.191 
.179 
.055 
.045 
.111 
-071 
.117 
.048 
.048 
.048 
.048 
.048 


.580 
.634 
.634 
.634 
.538 
.628 
.644 
.458 
.435 
.397 
.610 
.389 
.616 
.616 
.616 
.616 
.616 


2.255 

.088 
.088 
.088 
.310 
.310 
.310 
2.043 
.934 
2.23 
3.0 
.275 
.669 
14.62 
14.62 
14.62 
14.62 


1.64 

1.82 
1.82 
1.46 
1.25 
1.25 
1-25 

4.02 
3.94 
4.49 
18.5 
1.06 
2.74 
1.7 


.223 

.197 

.197 

.197 

.182 

.122 

.047 

.437 

.567 

.327 

.345 

.311 

.247 

.38 

.38 

.38 

.38 


.18 


Sauterne 


.18 


Pomard 


.18 


Rhine wine 


.18 
.18 

.18: 
.18. 
.18; 


Sherry, dry 


.18 


Madeira 


.18 
.18 


Marsala 


.026 


Port , 


.026 




.026 


Tokay 


.026 


Catawba 


.026 
.026 







Cider is the fermented juice of the apple, prepared very much in the 
same way as wine is from grape-juice and containing 3.5 to 7.5 per cent, of 
alcohol. It is very prone to acetous fermentation, which renders it sour 
and not only unpalatable, but liable to produce colic and diarrhoea with 
those not hardened to its use. 

Spirits are alcoholic beverages, prepared by fermentation and distilla- 
tion. They differ from beers and wines in containing a greater propor- 
tion of alcohol, and in not containing any of the non-volatile constituents 
of the grains or fruits from which they are prepared. Besides alcohol 
and water they contain acetic, butyric, valerianic and cenanthic ethers, 
to which they owe their flavor; sometimes tannin and coloring matter 
derived from the cask; amylic alcohol remaining after imperfect purifica- 
12 



178 GENERAL MEDICAL CHEMISTRY. 

lion; sugar intentionally added; and caramel. It is to the last-named sub- 
stance that all dark spirits owe their color; although, after long keeping 
in wood a naturally colorless spirit assumes a straw color. 

The varieties of spirituous beverages in common use are: 

Brandy ', spiritus vini gallici (U. S., Br.), obtained by the distillation 
of wine, and manufactured in France and in California and Ohio. It is 
of sp. gr. 0.929 to 0.934, is dark or light in color, according to the quantity 
of burnt sugar added, and contains about 1.2 per cent, of solid matter, of 
which 0.05 to 0.2 per cent, is ash. An inferior grade of brandy is pre- 
pared in wine-growing countries from the marc, or mass of grape-pulp, 
etc., left in the wine-press. 

American whiskey, spiritus frumenti (U. S.), prepared from wheat, 
rye, barley, or Indian corn; has a specific gravity of 0.922 to 0.937 and 
contains 0.1 to 0.3 per cent, of solids. Its color is due partly to coloring 
matter from the wood of the cask, but mainly to added caramel. 

Scotch and Irish whiskies, colorless spirits distilled from fermented 
grains; sp. gr. 0.915 to 0.920, having a peculiar smoky flavor produced by 
drying the malted grain by a peat fire. 

Gin, also distilled from malted grain, sp. gr. 0.930 to 0.944, flavored 
with juniper and sometimes fraudulently with turpentine. 

Hum. — A spirit distilled from molasses, and varying in color and 
flavor from the dark Jamaica rum to the colorless St. Croix rum. The 
former is of sp. gr. 0.914 to 0.926, and contains one per cent, of solid 
matter, of which 0.1 per cent, of ash. 

Liqueurs are spirits sweetened and flavored with vegetable aromatics, 
and frequently colored; anisette is flavored with aniseed; absinthe, with 
wormwood; curagoa, with orange-peel; kirschioasser, with cherries, the 
stones being cracked and the spirits distilled from the bruised fermented 
fruit; kummel,vf\th cummin and caraway seeds; maraschino, with cherries; 
noyeau, with peach and apricot kernels. 

Propyl Hydrate. 

Primary propyl alcohol — Ethyl carbinol — C 8 H 7 OH — is produced, 
along with ethylic alcohol, during fermentation, and obtained by fractional 
distillation of marc brandy, from cognac oil, huilede marc (not to be con- 
founded with oil of wine), an oily matter, possessing to a high degree 
the flavor of brandy, which separates from marc brandy, distilled at high 
temperatures; and from the residues of manufacture of alcohol from beet- 
root, grain, molasses, etc. It is a colorless liquid, has a hot alcoholic 
taste, and a fruity odor; it boils at 96.7°; and is miscible with water. It 
has not been put to any use in the arts. Its intoxicating and poisonous 
actions are greater than those of ethyl alcohol. It exists in small 
quantity in cider. 

There exists a secondary propyl alcohol, ox isopropyl alcohol or di- 
methyl carbinol — CH (CH 3 ) 2 HO — which is formed by the action of 
nascent hydrogen upon acetone; it boils at 86°. 

Butyl Alcohols— C 4 H 9 OH. 

Theoretically there are four possible butyl alcohols; two primary, one 
secondary, and one tertiary ; of these three have been obtained : 

Primary, normal butyl alcohol — Butyl alcohol of fermentation — Pro- 



AMYLIC ALCOHOLS. 179 

pyl carbinol — CH 3 — CH 2 — CH a — CH 2 OH — is formed in small quantities 
daring alcoholic fermentation, and may be obtained by repeated fractional 
distillation from the oily liquid left in the rectification of vinic alcohol. It 
is a colorless liquid; boils at 114.7°; soluble in 10 parts water, from which 
it separates on the addition of a salt soluble in water. It is more actively 
poisonous than ethyl or methyl alcohol. 

Secondary butyl alcohol; ethyl-methyl carbinol — CH 3 — CH ^p-r^TT 

a liquid which boils at 99°. 

CH S \ 
Tertiary butyl alcohol; trimethyl carbinol, CH 3 — COH — a crystalline 

CH S / 
solid, which fuses at 20° — 25°, and boils at 82°. 



Amylic Alcohols— C b H n OH. 

Of the eight amylic alcohols whose existence theoretical considerations 
point out as possible (see p. 152), seven have been separated. The sub- 
stance usually known as amylic alcohol, potato spirit, fusel oil, alcohol 
amylicum (U.S., Br.), is a mixture in varying proportions of the two 

primary alcohols; ^NcH—CH — CH 2 OH and CH ~ ch\/ CH "~" CH * 

OH; the former differing from the latter in that it deviates the plane of 
polarization to the left ([«] = — 4° 36"); in its boiling-point being 2° 
lower, and in the greater solubility of the amyl-sulphate of barium ob- 
tained from it. 

It is formed during alcoholic fermentation of glucose in greater 
abundance than any of the alcohols other than the ethylic; owing to its 
high boiling-point, it is in great part retained in the oily material which 
collects in the still during the rectification of alcohol and spirits; a por- 
tion, however, passes over and is removed by subsequent treatment (see 
below). 

It is obtained from the last milky products of rectification of alcoholic 
fluids made from grain or potatoes; these are shaken with water to re- 
move ethyl alcohol, the supernatant oily fluid is decanted, dried by con- 
tact with fused calcium chloride, and distilled; that portion which passes 
over between 128° and 132° being collected. 

It is a colorless, oily liquid, has an acrid taste and a peculiar odor, at 
first not unpleasant, afterward nauseating and provocative of severe 
headache; it boils at 132° and crystallizes at —20°; sp.gr. 0.8184 at 15°; 
it mixes with alcohol and ether, but not with water. It burns difficultly 
with a pale blue flame. 

When exposed to air it oxidizes very slowly; quite rapidly, however, 
in contact with platinum-black, forming valerianic acid. The same acid, 
along with other substances, is produced, by the action of the more 
powerful oxidants upon amyl alcohol. 

Chlorine attacks it energetically, forming amyl chloride, hydrochloric 
acid, and other chlorinated derivatives. Sulphuric acid dissolves in amyl 
alcohol, with formation of amyl-sulphuric acid, S0 4 (C r H n )H, correspond- 
ing to ethyl-sulphuric acid. It also forms similar acids with phosphoric, 
oxalic, citric, and tartaric acids. 



180 GENERAL MEDICAL CHEMISTRY. 

Although not fragrant itself, its ethers, when dissolved in ethyl alco- 
hol, have the taste and odor of various fruits, and are used in the prepa- 
ration of artificial fruit-essences. Amyl alcohol is also used in analysis 
as a solvent, particularly for certain alkaloids, and in pharmacy for the 
artificial production of valerianic acid and the valerianates. 

Its vapor, when inhaled, produces severe headache, a sense of suffo- 
cation, giddiness, and, in large doses, death. The liquid, taken internally, 
especially when in alcoholic solution, is much more actively poisonous 
than ethylic alcohol. Even in very dilute solution it produces the rapid 
intoxication, and severe headache and vertigo, which are prominent ef- 
fects of inferior whiskey. 

To free spirits of amyl alcohol, to defuselate them, advantage is usu- 
ally taken of the absorbent power of freshly burnt wood charcoal, which 
is either placed in the still or made into a filter, through which the spirit 
is passed after distillation, or, preferably, the vapor from the still is made 
to pass through a layer of charcoal before condensation. 

Spirits properly freed of fusel oil give off no irritating or foul fumes 
when hot; they are not colored red when mixed with three parts ethyl 
alcohol and one part strong sulphuric acid; they are not colored red or 
black by ammoniacal silver nitrate solution ; when one hundred and fifty 
parts of the spirit mixed with one part potash, dissolved in a little water, 
are evaporated down to fifteen parts, and mixed with an equal volume of 
dilute sulphuric acid, no offensive odor should be given off. 

No practical interest attaches to the alcohols of this series interme- 
diate between amvl alcohol and 



Cetyl Hydrate. 

Cetylic alcohol — Ethal — C 16 H 33 OH — is obtained by the saponification 
of spermaceti (its palmitic ether) by potash. It is a white, crystalline 
solid, fusible at 49°, and capable of distillation at a high temperature; 
insoluble in water; soluble in alcohol and ether; tasteless and odorless. 

Ceryl hydrate — C 27 H 5ft OH — cerylic or cerotic alcohol, and Myrieyl 
hydrate — C 80 H 61 OH — myricic or mellissic alcohol — are obtained as white, 
crystalline solids; the former from China wax; the second from beeswax, 
by saponification by potash. 



SIMPLE ETHERS. 

Oxides of Alcoholic Radicals of the Series dH^^. 

Methyl Oxide. 

pTT \ 

Methylic ether, C 2 H 6 0— prr 3 !• O — isomeric with ethylic alcohol, is ob- 
tained by the action of sulphuric and boric acids upon methyl alcohol, or 
by the action of silver oxide upon methyl iodide. 

It is a colorless gas, has an ethereal odor, burns with a pale flame, 
liquefies at —36°, and distils at —21°; is soluble in water, ethyl alcohol, 
and sulphuric acid, less abundantly in methyl alcohol. 



ETHYL OXIDE. 181 



Ethyl Oxide. 



Ethylic ether — Ether — Sulphuric ether — ^Ether fortior (U. S.) — ^Ether 

riu ] 

purus (Br.) — C 4 H 10 O — p 2 Ti 6 r O — was discovered in the sixteenth cen- 
tury by Val. Cordus, who called it oleum vini dulce. 

It is obtained by the action of sulphuric acid upon alcohol, whence the 
name of " sulphuric ether " is improperly given it. A mixture is made 
of five parts alcohol, ninety per cent., and nine parts of concentrated 
sulphuric acid, in a vessel surrounded by cold water. This mixture is 
introduced into a retort, over which is conveniently arranged a vessel 
from which a slow stream of alcohol can be made to enter the retort. Heat 
is applied by a sand-bath, and the addition of alcohol is so regulated that 
the temperature does not rise above 140°. The retort is connected with 
a well-cooled condenser, and the process continued until the temperature 
in the retort rises above the point indicated. It is important that the tube 
by which the alcohol is introduced be drawn out to a small opening, and 
dip well down below the surface of the liquid. The distillate thus ob- 
tained contains, besides ether, alcohol, water, and gases resulting from the 
decomposition of the alcohol and sulphuric acid, notably sulphur dioxide. 
It is subjected to a first purification by shaking with water containing 
potash or lime, decanting the supernatant ether, and redistilling. The 
product of this process is "washed ether" or "aether, U. S." It is still 
contaminated with water and alcohol, and when desired pure, as for pro- 
ducing anaesthesia and for processes of analysis, it is subjected to a second 
purification. It is again shaken with water, decanted after separation, 
shaken with recently fused calcium chloride and newly burnt lime, with 
which it is left in contact twenty-four hours, and from which it is then 
distilled. 

It was known at an early day that a small quantity of sulphuric acid 
is capable of converting a large quantity of alcohol into ether, and that 
at the end of the process the sulphuric acid remains in the retort unal- 
tered, except by secondary reactions. A metaphysical explanation of the 
process was found in the assertion that the acid acted by its mere presence, 
by catalysis, as it was said; in other words, it acted because it acted, a 
very ready but a very feminine method of explaining what is not under- 
stood, which, we are sorry to say, is still invoked by some authors as a 
covering for our ignorance of the rationale of certain chemico-physiologi- 
cal phenomena. 

It was only in 1850 that Alex. Williamson, by a series of ingenious 
and carefully conducted experiments, determined the true nature of the 
process. In the conversion of alcohol into ether, an intermediate sub- 
stance, sulphovinic acid, plays an important part, being alternately formed 
at the expense of the alcohol, and destroyed with formation of ether and 
regeneration of sulphuric acid. At first sulphuric acid and alcohol act 
upon each other, molecule for molecule, to form water and sulphovinic 



acid : 



c '\}° + S h.:}°* = 1}° + J|^°» 



182 GENERAL MEDICAL CHEMISTRY. 

The new acid, as soon as formed, reacts with a second molecule of 
alcohol, with regeneration of sulphuric acid and formation of ether: 

c;h:} o. + c «%lo = s 24o„ + &£»! 



H ) H J ■ ~ H . 1 ' C.H. ) 

Theoretically, therefor, a given quantity of sulphuric acid could con- 
vert an unlimited amount of alcohol into ether; such would also be the 
case in practice, were it not that the acid gradually becomes too dilute, by 
admixture with the water formed during the reaction, and at the same 
time is decomposed by secondary reactions, into which it enters with im- 
purities in the alcohol; causes which in practice limit the amount of ether 
produced to about four to five times the bulk of acid used. 

Properties. — Ether is a colorless, limpid, mobile, highly refracting- 
liquid; it has a sharp, burning taste, and a peculiar, tenacious odor, char- 
acterized as ethereal. Sp. gr. 0.723 at 12.5°, and 0.7364 at 0°; it boils at 
34.5°, and crystallizes at — 31°. Its tension of vapor is very great, especially 
at high temperatures; it should, therefor, be stored in strong bottles, and 
should be kept in situations protected from elevations of temperature. It 
is exceedingly volatile, and, when allowed to evaporate freely, absorbs a 
great amount of heat, of which property advantage is taken to produce 
local anaesthesia, the part being benumbed by the cold produced by the 
rapid evaporation of ether sprayed upon the surface. Water dissolves one- 
ninetieth its weight of ether, and ether dissolves one thirty-sixth its weight 
of water. Ethylic and methylic alcohols are miscible with it in all pro- 
portions. Ether is an excellent solvent of many substances not soluble in 
water and alcohol, while, on the other hand, it does not dissolve many sub- 
stances soluble in those fluids, properties which are of great value in prox- 
imate organic analysis. The resins and fats are readily soluble in ether; 
the salts of the alkaloids and many vegetable coloring matters are soluble 
in alcohol and water, but insoluble in ether, while the free alkaloids are 
for the most part soluble in ether, but insoluble, or very sparingly soluble, 
in water. 

Ether, whether in the form of vapor or of liquid, is highly inflammable; 
the liquid burns with a luminous flame. The vapor forms with air a vio- 
lently explosive mixture; it is denser than air, through which it falls and 
diffuses itself to a great distance; and great caution is therefor required 
in handling ether in a locality in which there is a light and fire, especially 
if the fire be near the floor. 

Pure ether is neutral in reaction, but, on exposure to air or oxygen, 
especially in the light, it becomes acid from the formation of a small quan- 
tity of acetic acid. 

Sulphuric acid mixes with ether with elevation of temperature and for- 
mation of sulphovinic acid; sulphuric anhydride forms ethyl sulphate. 
Nitric acid, aided by heat, oxidizes ether to carbon dioxide and acetic and 
oxalic acids. Ether, saturated with hydrochloric acid and distilled, yields 
ethvl chloride. 

Chlorine, in the presence of water, oxidizes ether, with formation of 
aldehyde, acetic acid, and chloral. In the absence of water, however, a 
series of products of substitution are produced, in which two, four, and 
ten atoms of hydrogen are replaced by a corresponding number of atoms 
of chlorine. These substances in turn, by substitution of alcoholic rad- 
icals, or of atoms of elements, for atoms of chlorine, give rise to other de- 
rivatives. 



MONOBASIC ACIDS. 183 

Ether is largely used in the chemical arts, in pharmacy, and in the; 
laboratory as a solvent, in the preparation of compound ethers, and for the 
production of cold. Its chief use in medicine is as an anaesthetic, being the 
safest and most readily handled that we possess. When taken in overdose 
it causes death, although it is by no means as liable to give rise to fatal 
accidents as is chloroform, and, as it seems to be without direct action upon 
the nerve-centres. Patients suffering from an overdose may, in the vast 
majority of cases, be resuscitated by artificial respiration and the induced 
current, one pole to be applied to the nape of the neck, and the other 
carried across the body just below the anterior attachments of the dia- 
phragm. 

In cases of death from ether the odor is generally well marked in the 
clothing and surroundings, and especially on opening the thoracic cavity. 
In the analysis it is sought for in the blood and lungs at the same time 
as chloroform (q. v.). 

The oxides of the remaining* alcoholic radicals mav be obtained bv 
processes similar to those used in the preparation of ethylic ether. 

Mixed ethers differ from the simple ethers (which may be regarded 
as water in which both atoms of hydrogen are replaced by like alcoholic 

radicals, /Vtt 5 [ O — ethylic ether) in that the two atoms of hydrogen 

pTT -J 

are replaced by unlike alcoholic radicals, p tt 3 [• O, methyl-ethyl oxide. 

They may be readily obtained by the action of the iodide of one alco- 
holic radical upon the potassium or sodium oxide of the other: 

CH i} + c ^}° = N i} +c <3i:}° 

Methyl iodide. Ethyl sodium Sodium iodide. Ethyl methyl 
oxide. oxide. 

As with each alcoholic iodide there can be formed as many mixed 
ethers as there are other monoatomic alcohols, it may be readily under- 
stood that substances of this class are very numerous. 

None of them have hitherto been applied to industrial or medicinal 
uses. 



MONOBASIC ACIDS. 

Series C n H 2n 2 . 

The members of this series, although formed in a variety of ways, 
may be considered as derived from the alcohols of the series C n H 2 „ +3 0, 
by the substitution of an atom of oxygen for two atoms of hydrogen, by 
oxidation of the radical. 

As the higher terms exist in the fats, and as the lower members of 
the series are volatile, they are frequently designated as the volatile fatty 
acids. They form an homologous series, the known terms of which are 
given in the table on following page. 

They all exist in nature, either free or in combination as salts or 
ethers, some of which are important articles of food, and others sub- 
stances valuable as medicinal agents. 



184 



GENERAL MEDICAL CHEMISTRY. 



Name. 


Formula. 


Fusing- 

point. 


Boiling- 

• point. 


Formic acid 


CHO,H 
C,H,0,H 

C.HAH 
C,H,0 3 H 

C.H.O.H 

C,H n O,H 

0,H l ,0,H 

C.H 15 O a H 
0,H„0,H 

C 18 H„0 2 H 
0„H„0,H 

C„H S1 2 H 
C„H JS 0,H 
C 1S H„0,H 
C„H jg O,H 

C..H..O.H 
C„H„O s H 

C„H m O,H 


1° 

17° 
-20° 

'r' 

14°' 

18° 

27° 

43.5° 

53.8° 

62° 

60° 

69° 

75° 

76° 

tyryo 

78° 
88° 


100° 


Acetic acid 


119 


Propionic acid 


140 


Butyric acid 


160 


Valerianic acid. . . , 


175 


Caproic acid 


198 




212 


Caprylic acid 


236 


Pelarsronic acid 


260 


Laurie acid 


• • • * 

9 • • 
■ • ♦ 




Myristic acid 




Palmitic acid 




Marsraric acid 




Stearic acid 




Arachic acid 












Cerotic acid 




Melissic acid 











Formic Acid— CH O — 



CHO 
H 



O 



Is widely distributed in the animal and vegetable kingdoms. As its 
name implies, it exists in the acid secretion of red ants, from whose bod- 
ies it was first obtained; it occurs also in the stinging hairs of certain in- 
sects, in the blood, urine, bile, perspiration, and muscular fluid of man, in 
the stinging-nettle, in the leaves of trees of the pine family, and, 
finally, in certain mineral waters. 

Formic acid is also produced in a number of reactions. By the oxida- 
tion of many organic substances, sugar, starch, fibrin, gelatin, albumin, 
etc. By the action of potash upon chloroform and kindred bodies. By 
the action of mineral acids on hydrocyanic acid. During the fermentation 
of diabetic urine. By the direct union of carbon monoxide and water: 



CO + HO: 



C0 2 H 2 . 



By the decomposition of oxalic acid under the influence of glycerin at 
about 100°: 

C 2 4 H 2 = C0 2 + C0 2 H 2 . 

The last is the reaction utilized in obtaining formic acid. 

It is a colorless liquid, having a sharp, acid taste, and a penetrating 
odor; when brought in contact with the skin it acts as a vesicant; it boils 
at 100° at the normal barometric pressure, and, when pure, crystallizes at 
0°; it is miscible with water in all proportions. 

The mineral acids decompose it into water and carbon monoxide; 
oxidizing agents convert it into water and carbon dioxide; alkaline hy- 
drates decompose it with formation of a carbonate and liberation of hy- 
drogen; it acts as a reducing agent with the salts of the noble metals. 



ACETIC ACID. 185 



Acetic Acid. 



Acetyl hydrate — Hydrogen acetate — Pyroligneous acid — Acidum aceti- 

eum (U. S., Br.) — C 2 H 3 2 H-°' H 3° I O.— Although in its dilute form, 

as vinegar, it has been known from remote antiquity, the pure acid was 
only obtained in the last century. 

It is produced in a great number of reactions, the principal of which 
are : 

First. — By the oxidation of alcohol : 

C 2 H 6 0+0 2 =C 2 H 4 2+ H Q 0. 

Second. — By the dry distillation of wood. 

Third. — By the decomposition of natural acetates by mineral acids. 

Fourth. — By the action of potash in fusion on sugar, starch, oxalic, 
tartaric, citric acids, etc. 

Fifth. — By the decomposition of gelatin, fibrin, casein, etc., by sul- 
phuric acid and manganese dioxide. 

Sixth. — By the action of carbon dioxide upon sodium methyl : 

C0 2 + NaCH 3 =C 2 H 3 2 Na, 

and decomposition of the sodium acetate so produced. 

The acetic acid used in the arts and in pharmacy is prepared by the 
destructive distillation of wood, which is heated in an iron retort con- 
nected with a condensing system. The products of the distillation, 
which vary with the nature of the wood used, are numerous. Charcoal 
remains in the retort, while the distilled product consists of an acid, 
watery liquid, a tarry material, and gaseous products. One hundred 
parts of wood yield usually: 

Charcoal 28 — 30 parts. 

Acid water 23 — 30 parts. 

Tar 7 — 10 parts. 

Gas 37 — 30 parts. 

The gases are carbon dioxide, carbon monoxide, and hydrocarbons; they 
are sometimes used for illuminating purposes, but are usually directed 
into the furnace, where they serve as fuel. The tar is a mixture of em- 
pyreumatic oils, hydrocarbons, phenol, oxyphenol, acetic acid, ammonium 
acetate, etc., and is used almost exclusively for the preservation of cord- 
age and wood in ships. 

The acid water is very complex, and contains, besides acetic acid, 
formic, propionic, butyric, valerianic, and oxyphenic acids, acetone, naph- 
thalene, benzene, toluene, cumene, creasote, methyl alcohol, and methyl 
acetate, etc. Partially freed from tar by decantation, it is a brown, acid 
liquid, having a disagreeable, empyreumatic odor. It still contains about 
twenty per cent, of tarry and oily material, and about four per cent, of 
acetic acid; this is the crude pyroligneous acid of commerce. 

The crude product is subjected to a first purification by distillation; 
the first portions are collected separately and yield meth}''l alcohol (q. v.); 
the remainder of the distillate is the distilled pyroligneous acid of com- 



186 



GENERAL MEDICAL CHEMISTRY. 



merce, used to a limited extent as an antiseptic, but principally for the 
manufacture of acetic acid and the acetates. It can only be freed from the 
impurities which it still contains by chemical means; to this end slacked 
lime and chalk are added, at a gentle heat, to neutralization; the liquid 
is boiled and allowed to settle twenty-four hours; the clear liquid, which 
is a solution of calcium acetate, is decanted and evaporated; the calcium 
salt is converted into sodium acetate, which is then purified by calcina- 
tion at a temperature below o30°, dissolved, filtered, and recrystallized; 
the salt is then decomposed by a proper quantity of sulphuric acid, and 
the liberated acetic acid separated by distillation. 

The product so obtained is a solution of acetic acid in water, contain- 
ing thirty-six per cent, of true acetic acid, and being of sp. gr. 1.047, 
United States (the acid of the British Pharmacopoeia is weaker — thirty- 
three per cent., C 2 H 4 2 , and sp. gr. 1.044). 

When pure acetic acid is required, recourse is had to the decomposi- 
tion of a dry acetate by heat; it is known as glacial acetic acid. 

Acetic acid is a colorless liquid at ordinary temperatures; below 17°, 
when pure, it is a crystalline solid. It boils at 119°; sp. gr. 1.0801 at0°; 
its odor is penetrating and acid; when brought in contact with the skin 
it destroys the epidermis and causes vesication; it mixes with water in all 
proportions, the mixtures being less in volume than the sum of the volumes 
of the constituents. The specific gravities of the mixtures gradually in- 
crease up to that containing twenty-three per cent, of water, after which 
they again diminish, and all the mixtures containing more than forty- 
three per cent, of acid are of higher specific gravity than the acid itself. 
In the following table are given the specific gravity of acids of different 
degrees of concentration at 15° C: 



Acetic acid. 


Specific 


Acetic a cirl, 


Specific 


Acetic acid, 


Specific 


Acetic acid, 


Specific 


per cent. 


gravity. 


per cent. 


gravity. 


per cent. 


gravity. 


per cent. 


gravity. 





0.9992 


26 


1.0363 


51 


1.0623 


76 


1.0747 


1 


1.0007 


27 


1.0375 


52 


1.0631 


77 


1.0748 


2 


1.0022 


28 


1.0388 


53 


1.0638 


78 


1.0748 


3 


1.0037 


29 


1.0400 


54 


1.0646 


79 


1.0748 


4 


1.0052 


30 


1.0412 


55 


1.0653 


80 


1.0748 


5 


1.0067 


31 


1.0424 


56 


1.0660 


81 


1.0747 


6 


1.0083 


32 


1.0436 


57 


1.0666 


82 


1.0746 


7 


1.0098 


33 


1.0447 


58 


1.0673 


83 


1.0744 


8 


1.0113 


34 


1.0459 


59 


1.0679 


84 


1.0742 


9 


1.0127 


35 


1.0470 


60 


1.0685 


85 


1.0739 


10 


1.0142 


36 


1.0481 


61 


1.0691 


86 


1.0736 


11 


1.0157 


37 


1.0492 


62 


1.0697 


87 


1.0731 


12 


1.0171 


38 


1.0502 


63 


1.0702 


88 


1.0726 


13 


1.0185 


39 


1.0513 


64 


1.0707 


89 


1.0720 


14 


1.0200 


40 


1.0523 


65 


1.0712 


90 


1.0713 


15 


1.0214 


41 


1.0533 


66 


1.0717 


91 


1.0705 


16 


1.0228 


42 


1.0543 


67 


1.0721 


92 


1.0696 


17 


1.0242 


43 


1.0552 


68 


1.0725 


93 


1.0686 


18 


1.0256 


44 


1.0562 


69 


1.0729 


94 


1.0674 


19 


1.0270 


45 


1.0571 


70 


1.0733 


95 


1.0660 


20 


1.0284 


46 


1.0580 


71 


1.0737 


96 


1.0644 


21 


1.0298 


47 


1.0589 


72 


1.0740 


97 


1.0625 


22 


1.0311 


48 


1.0598 


73 


1.0742 


98 


1.0604 


23 


1.0324 


49 


1.0607 


74 


1.0744 


99 


1.0580 


24 


1.0337 


50 


1.0615 


75 


1.0746 


100 


1.0553 


25 


1.0350 















ACETIC ACID. 187 

The vapor of acetic acid burns with a pale, bluish flame; when passed 
through a tube heated to redness it is decomposed, a mixture of combus- 
tible gases being given off and a carbonaceous residue remaining in the 
tube. The pure acid only decomposes calcic carbonate when diluted with 
water; and when mixed with alcohol does not redden litmus paper. 

Sulphuric acid, aided by heat, decomposes and blackens acetic acid; 
sulphur and carbon dioxides are given off. The presence of acetic acid 
may be recognized by this and by the following reactions: with silver 
nitrate, a white, crystalline precipitate, partially dissolved by heat; no 
reduction of silver on boiling the mixture. When it is heated with small 
quantities of alcohol and sulphuric acid, acetic ether is given off, and may 
be recognized by its odor. When an acetate is calcined with a small Quan- 
tity of arsenic trioxide, the foul odor of cacodyl oxide is observed. 

Chlorine acts upon acetic acid slowly under ordinary conditions, but 
actively under the influence of direct sunlight, producing monochlor- 
acetic acid, C 2 H 3 C10 2 ; dichloracetic acid, C 2 H 2 C1 2 2 ; and trichloracetic 
acid, C 2 HC1 3 2 . The last-named is obtained by exposing glass-stoppered 
bottles (well closed) filled with dry chlorine, and containing a small quan- 
tity of glacial acetic acid, to the direct rays of the sun for a day or more. 
It it an odorless, crystalline solid, which fuses at 4G°, and distils at 195° — 
200°. It is strongly acid, and has been used in medical practice as a pow- 
erful vesicant. 

Acetic acid is used in pharmacy in the preparation of many sub- 
stances. The Acidum acetictim dilutum (U. S., Br.) is of sp. gr. I.00G, 
and contains 4.5 per cent, of true acetic acid; its chief use is in the prep- 
aration of the aceta or medicated vinegars, improperly so called, which, 
whether they be made with dilute acetic acid, or with distilled vinegar, 
do not contain those constituents of vinegar which distinguish it from di- 
lute acetic acid. 

Vinegar is an acid liquid owing its acidity to acetic acid, and hold- 
ing certain fixed and volatile substances in solution. It has been known 
from early antiquity, and was the only acid known up to the end of the 
eighth century, when the Arabian alchemist Djafar, or Geber, as he is fre- 
quently called, discovered nitric acid. 

It is obtained from some liquid containing ten per cent, or less of 
alcohol,, which is converted into acetic acid, either by simple oxidation, 
as under the influence of platinum black, or, as in the industrial manufac- 
ture of vinegar, by the transferring of atmospheric oxygen to the alcohol 
during the process of nutrition of a peculiar vegetable ferment, known as 
mycoderma aceti or, popularly, as mother of vinegar. Vinegar is now 
manufactured principally by one or two processes — the German method 
and that of Pasteur. In the former, the alcoholic fluid, which must also 
contain albuminous matter, is allowed to trickle slowly through barrels in 
which it meets near the top a diaphragm, pierced with a number of holes, 
through which pass short cords; from these it drops upon a thick layer 
of beech-wood shavings, supported by a perforated false bottom. By a 
suitable arrangement of holes and tubes, an ascending current of air is 
made to pass through the barrel. The acetic ferment clings to the 
cords and shavings, and under its influence acetification takes place rap- 
idly, owing to the large surface exposed to the air. 

In Pasteur's process, which has to a great extent superseded the 
process formerly followed at Orleans, the ferment is sown upon the sur- 
face of the alcoholic liquid, contained in large, shallow, covered vats, 
from which the vinesrar is drawn off after acetification has been com- 



1S8 GENERAL MEDICAL CHEMISTRY. 

pleted ; the mother" is collected, washed, and used in a subsequent 
operation. 

The liquids from which vinegar is made are wine, cider, and beer, to 
which dilute alcohol is frequently added; the most esteemed being that 
obtained from white wine. 

Wine vinegar has a pleasant, acid taste and odor; it consists of water, 
acetic acid (about five per cent.), potassium bitartrate (about 2.5 grams 
per litre), alcohol, acetic ether, glucose, malic acid, mineral salts present 
in wine, a fermentescible, nitrogenized substance, coloring matter, etc. 
Its specific gravity is 1.020 to 1.025; its color varies from a pale yellow to 
a light reddish brown, according as it is made from white or red wine. 
When evaporated, it yields from 1.7 to 2.4 per cent, of solid residue. 

Vinegars made from alcoholic liquids .other than wine contain no po- 
tassium bitartrate, contain less acetic acid, and have not the aromatic 
odor of wine vinegar. Cider vinegar is of sp. gr. 2.0; is yellowish, has 
an odor of apples, and yields 1.5 per cent, of extract on evaporation. 
Beer vinegar is of sp. gr. 3.2; has a bitterish flavor, and an odor of sour 
beer; it leaves six per cent, of extract on evaporation. 

The principal adulterations of vinegar are: sulphuric acid, whose 
presence is indicated by an increase in the specific gravity, or more cer- 
tainly, by adding a few drops of the vinegar to some fragments of cane- 
sugar, and evaporating over the water-bath to dryness; in the presence 
of sulphuric acid the residue is dark brown or black. As commercial 
sulphuric acid always contains arsenic, that element has frequently been 
detected in adulterated vinegars. Water, an excess of which is indicated 
by a low power of saturation of the vinegar, in the absence of mineral 
acids. Two parts of good wine vinegar neutralize ten parts of sodium 
carbonate; the same quantity of cider vinegar, 3.5 parts; and of beer vine- 
gar, 2.5 parts of carbonate. Pyroligneous acid may be detected by the 
creosote-like odor and taste. Pepper, capsicum, and other acrid substan- 
ces, are often added to communicate fictitious strength; in vinegar so 
adulterated an acrid odor is perceptible after neutralization of the acid 
with sodium carbonate. Copper, zinc, lead, and tin frequently occur 
in vinegar which has been in contact with those elements, either during 
the process of manufacture or subsequently; they may be detected by 
methods elsewhere described. 

Distilled vinegar, Acetum destillatum (U. S.), is prepared by distilling 
vinegar in glass vessels; it contains none of the fixed ingredients of vine- 
gar, but its volatile constituents (acetic acid, water, alcohol, acetic ether, 
odorous principles, etc.), and a small quantity of aldehyde. It is a limpid, 
wholly volatile liquid, whose odor is similar to, but weaker than that of 
the kind of vinegar from which it was distilled, from which it also differs 
in being of less acid strength, as the boiling-point of acetic acid is higher 
than that of water. Dilute acetic acid is frequently called distilled vinegar. 

When dry acetate of copper is distilled, a blue, strongly acid liquid 
passes over; this, upon rectification, yields a colorless, mobile liquid, 
which boils at 56° C., has a peculiar odor, and is a mixture of acetic 
acid, water, and acetone, known to the older chemists as radical vinegar, 
and still used under that name in perfumery. 

Toxicology. — When taken internally, acetic acid and vinegar (the 
latter in doses of four to five fl. 3 )act as irritants and corrosives, causing 
in some instances perforation of the stomach, and death in from six to 
fifteen hours. Milk of magnesia should be given as an antidote, with the 
view to neutralizing the acid. 



BUTYRIC ACID. 189 

The presence of acetic acid, or of an acetate, may be recognized by 
the following tests : 

First. — When heated with sulphuric acid, acetic acid, recognizable 
by its odor, is given off. 

Second. — If a mixture of an acetate, sulphuric acid, and alcohol be 
heated, the apple odor of ethyl acetate is produced. 

Third. — Neutral solution of ferric chloride forms, with a neutral solu- 
tion of an acetate, a deep red liquid, which turns yellow on the addition 
of a free acid. 



Propionic Acid, C 3 H 6 — ° 3H& ° i O. 

This acid, discovered by Gottlieb in 1844, is formed in many decom- 
positions of organic substances. By the action of caustic potassa upon 
sugar, starch, gum, and ethyl cyanide; during fermentation, vinous or 
acetic, in wine, moist leather, calcium tartrate solution; in the distillation 
of wood, and during the putrefaction of peas, beans, etc.; by the oxida- 
tion of normal propylic alcohol, etc. It is best prepared by heating 
ethyl cyanide with potash until the odor of the ether has disappeared; 
the acid is then liberated from its potassium compound by sulphuric or 
phosphoric acid, and purified. 

It is a colorless liquid, sp. gr. 0.996, does not solidify at —21°, boils 
at 140°, mixes with water and alcohol in all proportions, resembles acetic 
acid in odor and taste. Its salts are soluble and crystallizable. 

Propionic acid is probably formed in the body as a product of oxida- 
tion of the fats and albuminoids, its presence, however, has not been 
demonstrated with certainty, although it has been said to exist in the 
perspiration, the contents of the stomach, in the vomit of cholera, and in 
fermented diabetic urine. 



Butyric Acid, C « H '° I O CH — CH — CH — CO,OH. 

Discovered bv Chevreul in butter; it exists in nature free and in com- 
bination, in its ethylic and glyceric ethers. It has been found in the 
milk, perspiration, muscular fluid, the juices of the spleen and of other 
glands, the urine, contents of the stomach and large intestine, faeces, and 
guano, in certain fruits, in yeast, in the products of decomposition of 
many vegetable substances, and in natural waters; in fresh butter in 
small quantity, more abundantly in that which is rancid. 

It is formed in a number of decompositions of organic substances. 
By the action of sulphuric acid and manganese dioxide, aided by heat, 
upon cheese, starch, gelatin, etc.; during the combustion of tobacco (as 
ammonium butyrate); by the action of nitric acid upon oleic acid; during 
the putrefaction of fibrin and other albuminoids; during a peculiar fer- 
mentation of glucose and starchy material in the presence of casein or 
gluten. This fermentation, known as the butyric, takes place in two 
stages; at first the glucose is converted into lactic acid: 

C.H II 0,=2(C,H,0 1 ), 



190 GENERAL MEDICAL CHEMISTRY. 

and this in turn is decomposed into butyric acid, carbon dioxide, and 
hydrogen : 

2C,H,0 8 =C ) H e O a +2CO s + 2H a . 

Butyric acid is now usually obtained from the animal charcoal which 
has been used in the purification of glycerine, in which it exists as cal- 
cium butyrate. It is also formed by subjecting to fermentation, at 25° — 
30°, a mixture composed of glucose 1 kilo, water to sp. gr. 10° Baume, 
chalk 0.5 kilo, cheese or gluten 0.1 kilo. The calcium butyrate is de- 
composed by sulphuric acid, and the butyric acid separated by distilla- 
ation. 

Butyric acid is a colorless, mobile liquid, having a disagreeable, persis- 
tent odor of rancid butter, and a sharp, acid taste, soluble in water, alcohoL 
ether, and methyl alcohol; boils at 164°, distilling unchanged; solidifies in 
a mixture of solid carbon dioxide and ether; sp. gr. 0.974 at 15°; a good 
solvent of fats. 

Sulphuric acid does not act upon butyric acid in the cold, and only 
slightly under the influence of heat. Nitric acid dissolves it unaltered in 
the cold, but, on the application of heat, oxidizes it to succinic acid. Dry 
chlorine under the influence of sunlight, and bromine under the influence 
of heat and pressure, form products of substitution with butyric acid. It 
readily forms ethers and salts, the latter being, for the most part, soluble 
in water. Its vapor is inflammable and burns with a blue flame. 

Butyric acid is formed in the intestine, by the process of fermentation 
mentioned above, at the expense of those portions of the carbohydrate 
elements of food which escape absorption, and is discharged with the 
faeces as ammonium butyrate. 

Isobutyric acid, an isomere of butyric acid, which boils at 152°, has 
also been found in human faeces. It corresponds to isobutyl alcohol, and 
has the composition — 

CH 3 / CH ~ C0 ' 0H - 



Valerianic Acids, C 5 H 10 O — C * H ^ 1 O. 

Corresponding to the four primary amylic alcohols, there are four 
amy lie or valerianic acids: 

I. CH — CH — CH — CH — CO,OH. 
II. CH/ CH ~ CH ~ C0 ' 0H - 
HI. CH _g|)CH-CO,OH. 

CH 3 \ 
IV. CH 3 — G— CO,OH. 
CH 8 / 



CAPROIC ACIDS. 191 

I. Normal valerianic acid — Putylformic acid — Propylacetic acid — 
is obtained by the oxidation of normal amylic alcohol. It is an oily liquid, 
boils at 184° — 185°, and has an odor resembing that of butyric acid. 

II., III. Ordinary valerianic acid — Delphinic acid^Phocenic acid 
— Isovaleric acid — Isopropyl acetic acid — Isobutylformic acid — Acidum 
valerianicum (U. S., Br.). — This acid was discovered in 1817 by Chevreul, 
in the oil of the porpoise {delphinium phoccenci), and subsequently in vale- 
rian root and in angelica root. It is formed during putrid fermentation or 
oxidation of albuminoid substances. It occurs in the urine and fasces in ty- 
phus, variola, and acute atrophy of the liver. It is also formed in a variety 
of chemical reactions and notably by the oxidation of amylic alcohol. 

It is prepared either by distilling water from valerian root, or, more 
economically, by mixing rectified amylic alcohol with sulphuric acid, 
adding, when cold, a solution of potassium dichromate, and distilling 
after the reaction has become moderated; the distillate is neutralized with 
sodium carbonate; and the acid is obtained from the sodium valerianate 
so produced, by decomposition by sulphuric acid and rectification. 

The properties and nature of the acid differ according to those of the 
amyl alcohol from which it is obtained. The active alcohol yields the acid, 

CH/ CH_ CH — C0 > 0H > 

which is itself optically active, which forms an uncrystallizable and ex- 
ceedingly soluble barium salt, and whose boiling-point is 172.5° — 173.5°. 

PIT \ 

The inactive alcohol yields by oxidation the acid, p-pr p-rr 3 /OH — 

CO, OH, which is optically inactive, whose barium salt is readily crystalliz- 
able and soluble in water to the extent of forty-eight parts in one hun- 
dred, and whose boiling-point is 174.5°. 

The identity of the acid obtained from valerian root and that obtained 
by the oxidation of amylic alcohol has frequently been called in question. 
The properties of the former show, however, that it is identical with the 
acid obtained by the oxidation of optically inactive amylic alcohol. The 
artificial product, being obtained from the commercial mixture of active 
and inactive alcohols, is a mixture in different proportions of the two acids 
mentioned above. 

The ordinary valerianic acid is an oily, colorless liquid, having a pene- 
trating odor, and a sharp, acrid taste. It solidifies at — 16°; boils at 173° 
—175°; sp. gr. 0.9343 — 0.9465 at 20°; burns with a white, smoky flame. 
It dissolves in thirty parts of water, and in alcohol and ether in all propor- 
tions. It dissolves phosphorus, camphor;, and certain resins. It forms 
salts and ethers called valerianates, some of which, as those of ammonium, 
zinc, quinine, atropine, bismuth, and iron, are used in medicine. 

IV. Trimethyl acetic acid — Pivalic acid — is a crystalline solid, which 
fuses at 35.5° and boils at 163.7°; sparingly soluble in water; obtained 
by the action of cyanide of mercury upon tertiary butyl iodide. 

Caproic Acids. 

Hexylic acids — C 6 H 12 2 — 6 "n O. — There probably exist quite a 

number of isomeres having the composition indicated above, some of 
which have been prepared from butter, cocoa-oil, and cheese, and by de- 
composition of amyl cyanide, or of hexyl alcohol. 



192 GENERAL MEDICAL CHEMISTRY. 

The acid obtained from butter, in which it exists as a glyceric ether, 
is a colorless, oily liquid, boils at 205°; sp. gr. 0.931 at 15°; has an odor 
of perspiration and a sharp, acid taste; is very sparingly soluble in water, 
but soluble in alcohol. The acid obtained from amyl cyanide deviates 
the plane of polarization to the right ([#]r = 2.43°); boils at 198°, and 
solidifies at —9°. 

CEnanthylic Acid. 

OH O ) 

Ileptylic acid, C,H M O a — 7 13 H j- O — exists in spirits distilled from 

rice and maize, and is formed by the action of nitric acid upon fatty sub- 
stances, especially upon castor oil. It is a colorless oil; boils at 212°; 
sp. gr. 0.9167 at 24°; soluble in alcohol and in ether. 

Caprylic Acid. 

OHO) 
Octylic acid, C 8 H 1B 2 — 8 1B rr [• O — accompanies caproic acid in but- 
ter, cocoa-oil, etc. It is solid, melts at 14° — 15°, and boils at 236°; almost 
insoluble in water; very soluble in alcohol and in ether. 

Pelargonic Acid. 

OHO) 
Nonylic acid, C 9 H 18 3 — 9 17 tt !■ O — exists in the volatile oil of ge- 
ranium, and is formed by the action of nitric acid upon essence of rue. 
It is a colorless oil; has a feeble odor; solidifies at 10°; boils at 260°; in- 
soluble in water; soluble in alcohol and ether. 

Capric Acid. 

OHO) 

Decylic acid, C 10 H au O 3 — 10 'Vr \ O — exists in butter, cocoa-oil, etc., 

associated with caproic and caprylic acids in their glyceric ethers, and in 
the residues of distillation of Scotch whiskey, as amyl caprate. It is a 
white, crystalline solid; melts at 27.5°; boils at 273°; insoluble in water; 
soluble in alcohol and ether; has a faint odor, resembling that of the goat. 

Laurie Acid. 

OHO) 
Zaurostearic acid, C 12 H 24 2 — 12 - 3 ^ > O — exists in laurel berries, 

cocoa-butter, and in other vegetable fats. It is a transparent, crystalline 
solid; melts at 43.5°; insoluble in water; readily soluble in alcohol and 
in ether. 

Myristic Acid, C 14 H 28 0,— C " H *^ i O, 

Exists in many vegetable oils, in cow's butter, and in spermaceti. It 
crystallizes in brilliant, colorless plates; fusible at 54°. 



STEARIC ACID. 193 



Palmitic Acid. 

C 1 IT O ) 

JEthalic acid, C 16 H 32 2 — 16 3 Vt > O — exists in palm-oil, in combi- 
nation when the oil is fresh, and free when the oil is old; it also enters 
into the composition of nearly all animal and vegetable fats. It is ob- 
tained from the fats, palm-oil, etc., by saponification with caustic potassa 
(see p. 285), and subsequent decomposition of the soap by a strong acid. 
It is also formed by the action of caustic potash in fusion upon cetyl 
alcohol (ethal), and by the action of the same reagent upon oleic acid. 

Palmitic acid is a white, crystalline solid; odorless; tasteless; lighter 
than water, in which it is insoluble; quite soluble in alcohol and in ether; 
fuses at 62°; distils unchanged with vapor of water. It is used in the 
manufacture of candles and of soaps. 



Margaric Acid, C 17 H 34 — C ^fi i O. 

Previous to 1852 this acid was supposed to exist as a glyceride in all 
fats, solid and liquid; in that year, however, Heintz showed that what had 
been taken for margaric acid was a mixture of ninety per cent, of palmitic 
and ten per cent, of stearic acid, and at the same time he obtained the 
true margaric acid by the action of potassium hydrate upon cetyl cyanide. 

It is a white, crystalline body; fusible at 59.9°; insoluble in water; 
soluble in alcohol and in ether. 



Stearic acid, C 18 H 36 0— C » H »«0 I O. 

This, the most abundant of the fatty acids, was discovered by Chevreul 
in 1811. It exists as a glyceride in all solid fats, and in many oils, and 
also free to a limited extent. 

To obtain it pure, the fat is saponified with an alkali, and the soap de- 
composed by hydrochloric acid; the mixture of fatty acids is dissolved in 
a large quantity of alcohol, and the boiling solution partly precipitated by 
the addition of a concentrated solution of barium acetate. The precip- 
itate is collected, washed, and decomposed by hydrochloric acid; the 
stearic acid which separates is washed and recrystallized from alcohol. 
The process is repeated until the product fuses at 70°. 

An impure stearic acid, mixed with palmitic and other acids, is pre- 
pared industrially on a large scale in the manufacture of stearin candles. 

Pure stearic acid is a colorless, odorless, tasteless solid; fusible at 69° 
— 70°; unctuous to the touch; insoluble in water; very soluble in alcohol 
and in ether. The alkaline stearates are soluble in water; those of cal- 
cium, barium, and lead are insoluble. 

Stearic and palmitic acids exist free in the intestine during the diges- 
tion of fats, a portion of which is decomposed by the action of the pan- 
creatic secretion into fatty acids and glycerin. The same decomposition 
also occurs in the presence of putrefying albuminoid substances. 

C IT * O ) 
Arachic acid, C ao H 40 O a — 20 3 Vr [• O — exists as a glyceride in pea- 
nut-oil (now largely used as a substitute for olive-oil), in oil of ben, and 
13 



194 GENERAL MEDICAL CHEMISTRY. 

in small quantity in butter. It is a crystalline solid, which melts at 75°, 
and solidifies at 73°; sparingly soluble in aqueous alcohol; soluble in ab- 
solute alcohol and ether. 

O TT O ) 
Benic acid — Benostearic acid— C 22 H 44 2 — 22 «„ V O — a solid, crys- 
talline body; fuses at 76°; solidifies at 70°; exists in oil of ben. 

n TT A j 

Hyaenic acid, C 26 H &0 O 2 — " "ji I O— exists in the fat, and espe- 
cially in the anal glands, of the hyena. 

Cerotic acid, C 27 H 64 2 — 27 63 jj I O — constitutes the bulk of that 

part of beeswax which is soluble in boiling alcohol, and may be obtained 
from China wax by dry distillation. 

A IT A j 

Melissic acid, C S0 H 60 O 8 — 30 69 „ I O — exists in beeswax. 



COMPOUND ETHERS. 

Methylic. 



ter, m a 



Methyl nitrate, prr 2 !■ O — is prepared by bringing togeth< 

retort, powdered potassium nitrate and a mixture of sulphuric acid and 
methyl alcohol; the action takes place at first in the cold, but the distil- 
lation must be completed at the temperature of the water-bath. The dis- 
tillate is purified by washing with water, and by repeated rectifications 
from massicot and calcium chloride. 

It is a colorless liquid; sp. gr. 1.182 at 22°; boils at 66°; burns with 
a yellow flame; its vapor detonates violently when heated above 150°. It 
is decomposed by potash into potassium nitrate and methylic alcohol; it 
dissolves ammonia, with formation of ammonium nitrate and methylamine. 
It is a good solvent of nitro-glycerine and of gun-cotton. 

Methyl nitrite, prr !• O — is obtained by heating methylic alcohol 

with nitric acid and copper. Below — 12° it is a yellowish liquid; above 
that temperature, a gas. Isomeric with nitromethane. 



Ethylic. 

Ethyl nitrate — Nitric ether — p tt 2 !• O — is obtained by distilling a 

mixture of one volume of nitric acid and two volumes of alcohol, in the pres- 
ence of urea, the last-named substance being added to prevent the forma- 
tion of the lower oxides of nitrogen. The first part of the distillate, con- 
sisting of alcohol, is discarded, and the distillation is stopped when the 
contents of the retort have been reduced to one-third the original bulk. 
The product is washed, dried by contact with calcium chloride, and rec- 
tified. 

Nitric ether is a colorless liquid, has a sweet taste, with a bitter 
after-taste ; sp. gr. 1.112 at 17°; boils at 85° — 86°; burns with a white 
flame. Its vapor, when heated, explodes violently on the approach of a 
flame. 



ETHYLIC ETHERS. 195 

Ethyl nitrite— Nitrous ether — c tt [ O — was obtained by Kunkel 

as early as 1681. 

Quite a number of processes have been suggested for obtaining this 
substance; the best consists of directing the nitrous fumes, produced by 
the action of nitric acid upon starch, under the influence of heat, into 
alcohol contained in a retort connected with a well-cooled receiver. 

An older process, still frequently used, is by acting upon alcohol di- 
rectly with nitric acid; the operation must be conducted in a capacious 
retort, and the gentle heat applied to start the reaction must be with- 
drawn as soon as the distillation begins. This method cannot be used on 
a large scale, owing to the violence of the action, and is also objection- 
able on account of the loss of alcohol required to reduce the nitric acid. 

Pure ethylic nitrate is a yellowish liquid; has a peculiar, apple-like 
odor, and a sweetish, sharp taste; sp. gr. 0.947; boils at 18°. Its vapor- 
ization produces a great diminution of temperature; the vapor is inflam- 
mable, burning with a white flame; very sparingly soluble in water; quite 
soluble in alcohol and ether. 

It is decomposed by warm water into alcohol, nitric acid, and nitro- 
gen dioxide; more rapidly by alkalies, with formation of malate and 
nitrate of the alkaline element, but without formation of acetate. It is 
energetically attacked by sulphuric acid, and also by sulphydric acid and 
the alkaline sulphides. Its vapor, when passed through a red-hot tube, 
is decomposed, yielding nitrogen, nitrogen dioxide, carbon monoxide, hy- 
drocarbons, water, ammonium cyanide and carbonate, an oily material, 
and carbon. When kept it is liable to spontaneous decomposition into 
nitrogen dioxide and malic acid, especially in the presence of water. 

Its vapor rapidly produces anaesthesia; it is not, however, used in 
medicine in its pure form, but only in alcoholic solution : Spiritus cetheris 
nitrosi(XJ. S., Br.), which also contains aldehyde. Owing to the presence 
of the last-named substance, and to the presence of water, the spirit is 
very liable to become acid, either from the formation of acetic acid by the 
oxidation of the aldehyde, or from the decomposition of the ether under 
the influence of water; a change which renders it unfit for use in many of 
the prescriptions in which it is frequently used, especially in that with po- 
tassium iodide, from which it liberates iodine. The presence of free acid 
may be detected by effervescence when the spirit is shaken with hydro- 
sodic carbonate. Its acidity may be corrected by shaking with potassium 
carbonate, and decanting, provided it does not contain water. 

Ethyl borates. — There are four ethylic borates, three of which cor- 
respond to the three acids, boric, metaboric, and tetraboric. The borate, 
B0 3 (C 2 H 5 ) 3 , is a colorless, mobile liquid, having a peculiar, agreeable odor, 
and a bitter taste; soluble, but decomposed, by water; soluble in alcohol 
and ether; burns with a green flame, giving off dense fumes of boric acid. 

Ethyl phosphates. — Four of these compounds are known: 

P0 4 (C 2 H 5 )H,, — Monethyl-phosphoric acid — Phosphovinic acid. 

P0 4 (C 2 H 5 ) 2 H — Diethyl-phosphoric acid. 

P0 4 (C 2 H 5 ) 3 — Triethyl phosphate — Phosphoric ether. 

P a O T (C 3 H 6 ) 4 — Tetrethylic pyrophosphate — Pyrophosphoric ether. 

Of these, the first two possess acid properties and form salts. There 
exist also numerous compounds similar in constitution to the ethyl phos- 
phates, in which one or more of the atoms of oxygen are replaced by 



196 GENERAL MEDICAL CHEMISTRY. 

atoms of sulphur, or of selenium, e. g., diethyl-sulphophosphoric acid, 
P0 3 S (C 2 H 5 ) 2 H, some of which also form salts. 

There are also four ethyl phosphites, two of which are acids and two 
neutral ethers. 

Ethyl sulphates. — These are two in number: 

S0 4 (C 2 H 5 ) — HEthyl-sulphuric, or sulphovinic acid. 
S0 4 (C 2 H 5 ) 2 — Ethyl-sulphate — Sulphuric ether. 

Ethyl-sulphuric acid, (C 2 H 5 ) V O — is formed as an intermediate pro- 

H ) 

duct in the manufacture of ethylic ether (q. v.). It is prepared by slowly 
adding sulphuric acid to an equal volume of alcohol, mixing and cooling 
as the addition progresses; when cold, the mixture is diluted with water, 
and barium carbonate is added to saturation; the clear liquid, on concen- 
tration, yields crystalline plates of barium ethyl-sulphate [S0 4 (C 2 H & )] 2 Ba", 
which, when exactly decomposed with sulphuric acid, liberates sulpho- 
vinic acid. 

Pure ethyl-sulphuric acid is a colorless, syrupy, highly acid liquid; sp. 
gr. 1.316; soluble in water and alcohol in all proportions; insoluble in ether. 

It decomposes slowly at ordinary temperatures, more rapidly when 
heated. When heated alone or with alcohol, it yields ether and sulphuric 
acid: 




When heated with water, it yields alcohol and sulphuric acid: 

HI Q _ C.H.) Q SOJ 

+ H j U - H \ U + H 2 ) U *' 




It forms crystalline salts, known as sulphov incites, one of which, 

sodium sulphovinate, S0 4 (C 2 H 5 )Na, has been used in medicine. It is a 

white, deliquescent solid, either crystalline with 10.78 per cent, of water 

of crystallization, or granular and anhydrous; the former fuses at 86°, the 

latter does not fuse, but is decomposed at 100°; it is soluble in 0.61 parts 

of water at 17°. Its solution should give no precipitate with barium 

chloride. 

SO ) 
Ethyl sulphate, /p tt \ 2 \ 2 — the true sulphuric ether, is obtained by 

passing vapor of sulphur trioxide into pure ethylic ether, thoroughly 
cooled; the product is purified by washing with water and milk of lime, 
and concentrating in vacuo. 

It is a colorless, oily liquid, has a sharp, burning taste, and the odor 
of peppermint; sp. gr. 1.120; it cannot be distilled without decomposition; 
in contact with water it is decomposed with formation of sulphovinic acid. 

By the action of an excess of sulphuric acid upon alcohol, by the dry 
distillation of the sulphovinates, and in the last stages of manufacture of 
ether, a yellowish, oily liquid, having a penetrating odor and a sharp, 
bitter taste, is formed; this is sweet or heavy oil of wine, and its ethereal 



ETIIYLIC ETHERS. 197 

solution is Oleum cethereum (U. S.). It seems to be a mixture of ethyl-sul- 
phate with hydrocarbons of the series C n H Sn . On contact with water or 
an alkaline solution, it is decomposed, sulphovinic acid is formed, and there 
separates a colorless oil, of sp. gr. 0.917, boiling at 280°, which is light oil 
of wine. This oil is polymeric with ethylene, and is probably cetene, 
C 16 H 32 ; it is sometimes called etherine or etherol; when cooled to — 35° it 
deposits crystals, which fuse at 110° and boil at 260°. 

OHO) 
Ethyl acetate — Acetic ether — p fr r O — is obtained by distilling 

a mixture of potassium or sodium acetate, sulphuric acid, and alcohol; the 
distillate is purified by washing with an alkaline solution and with water, 
dried by contact with calcium chloride, and rectified. It may also be ob- 
tained by passing carbon dioxide through an alcoholic solution of potas- 
sium acetate, and purifying as above. 

It is a colorless liquid; has an agreeable, ethereal odor; boils at 74°; sp. 
gr. 0.89 at 15°; soluble in six parts water, and in all proportions in methyl 
and ethyl alcohols and in ether; a good solvent of essences, resins, can- 
tharidine, morphine, gun-cotton, and, in general, of substances soluble in 
ether; burns with a yellowish white flame. 

Chlorine acts energetically upon ethyl acetate, producing products of 
substitution, varying according to the intensity of the light from C 4 H 6 
CIA to C 4 Cl e 2 . 

Ethyl formiate — Formic ether — nu !• O — is obtained by decom- 
position of a formiate by a process similar to that used in the preparation 
of the acetate, also by distilling a mixture of glycerin, oxalic acid, and 
alcohol; it is also formed in the manufacture of fulminating mercury. It 
is obtained as a commercial product by distilling a mixture of starch, 
alcohol, water, sulphuric acid, and manganese dioxide. 

It is a colorless liquid; has an odor resembling that of the peach; boils 
at 56°; sp. gr. 0.915 at 18°; burns with bluish flame; soluble in nine parts 
of water, and in all proportions in alcohol and ether. 

It is isomeric with methyl acetate: 



CHO) 


CAO > Q 


C.H.O, 


C.H.O, 


Ethyl formiate. 


Methyl acetate. 



The different arrangement of the atoms in the molecule is well shown 
by the action of alkalies upon the two substances, producing ethylic alco- 
hol and a formiate in one case, and methylic alcohol and an acetate in the 
other. 

Ethyl formiate. Potassium hydrate. Potassium formiate. Ethyl hydrate. 

°-&?}° + |}0 = ^i\0 + CH,J 

Methyl acetate. Potassium hydrate. Potassium acetate. Methyl hydrate. 

Ethyl acetate and formiate are largely used in combination with other 
compound ethers of methyl, ethyl, and amyl in the manufacture of fruit- 



198 



GENERAL MEDICAL CHEMISTRY. 



essences, which, with the exception of essence of orange, are rarely, if ever, 
made from the fruits after which they are named. In the following' table is 
given the composition, in cubic centimetres, added to one hundred parts 
of alcohol, of the principal artificial essences used in the manufacture of 
confectionery, The constituents used must be chemically pure: 



Artificial Fruit-Essences. 





































Cold saturated 




































alcoholic so- 


















o 
a] 








v 

-*-j 






Is 
'C 


bo 


lution of 






a 


0) 

£1 




4-> 

o 


0) 

as 
1 


E 
>>> 

±2 


.2 

o 


o 

N 

s 


c3 


<u 
—J 


>> 

o 

13 


V 


01 

>> 


M 
O 

'4- 




*2 


'5 

03 


•a 
1 




a 

■3 

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al 


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Si 

*-> 


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-t-> 


XI 


.£: 


.C 




JS 


01 


a 


s 


a 


K 


x 








5 
8 


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'4, 


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W 


W 
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w 


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Plum 




Apricot 




Peach 





The figures indicate the number of cubic centimetres to be added to 100 c.c. of alcohol. 

Other mixtures of ethers of the same class are used in the manufacture 
of imitation spirits. Ethyl formiate predominates in essence of rum, and 
ethvl pelargonate in essence of cognac. 

ccn 

Ethyl carbonates are two in number: C 2 H 5 [• 2 , ethyl-carbonic or 

H 

CO ) 
carbovinic acid, and /p tt \ \ 2 , ethyl carbonate or carbonic ether. The 

former is a monobasic acid, the latter a neutral body. By the action of 
ammonia upon ethyl carbonate in the cold ethyl carbonate or urethan, 
CO (NH 2 )0,C 2 H 6 , is formed; and under the influence of heat, urea, 
CO (NH,) 8 . 

Ethyl oxalates. — Oxalic acid, being dibasic, forms two series of 
ethers; of ethylic ethers there are C 2 4 (C 2 H 5 )H, ethyloxalic or oxalovinic 
acid, and C 2 4 (C 2 H 5 ), ethyl oxalate or oxalic ether. The former is a mono- 
basic acid, isomeric with succinic acid; the latter is neutral. 



Amylic. 

Amyl nitrate, p tt 2 f- O — is obtained by a process similar to that 

used for preparing the corresponding ethyl compound, by the distillation 
of a mixture of nitric acid and amylic alcohol in the presence of a small 
quantity of urea. It is a colorless, oily liquid; has an odor resembling 



AMYLIC ETHERS. 199 

that of bed-bugs, and a sweetish, burning taste; sp. gr. 0.994 at 10°; boils 
at 148°, with partial decomposition. 

Amyl nitrite — Amyl nitrous ether — ^ ^ I O — prepared by direct- 
ing the nitrous fumes, evolved by the action of nitric acid upon starch, 
into amyl alcohol contained in a retort heated over a water-bath, purifying 
the distillate by washing with an alkaline solution, and rectifying. 

It is a slightly yellowish liquid; sp. gr. 0.877; boils at 95°; its vapor 
explodes when heated to 260°; insoluble in water; soluble in alcohol in all 
proportions; vapor orange-colored. 

Alcoholic solution of potash decomposes it slowly, with formation of 
potassium nitrite and oxides of ethyl and amyl. When dropped upon 
fused potash, it ignites and yields potassium valerianate. 

Amyl nitrite is frequently impure ; its boiling-point should not vary 
more than two or three degrees from that given above. 

Amyl sulphates — Are the same in constitution as those of ethyl, 
and are obtained by similar methods. Amyl sulphuric acid is of historical 
interest, as it was by its formation that Williamson showed the true nature 
of the process of etherification. The amyl sulphate of barium, prepared 
from active amyl alcohol, is three times more soluble than that made from 
the inactive — a property which is utilized to separate the two alcohols. 

Amyl acetate, A tt [• O — Obtained by distilling a mixture of amyl 

alcohol, potassium acetate, and sulphuric acid. A limpid, colorless liquid; 
sp. gr. 0.8762 ; boils at 125° ; insoluble in water ; soluble in alcohol and 
ether. Its alcoholic solution is used as artificial pear-essence. 

Of the great number of other ethers of this series, there are none of 

particular practical importance until we reach 

C H O ) 
Cetyl palmitate, \% |V [• O — Also known as cetine, which is the 

• • 16 33 ' 

chief constituent of Spermaceti=cetaceu7ii (U. S., Br.). This is the con- 
crete portion, obtained by expression and crystallization from alcohol, of 
the oil contained in the cranial sinuses of the sperm-whale. It forms 
white crystalline plates ; fusible at 49° ; slightly unctuous to the touch ; 
tasteless, and almost odorless ; insoluble in water ; soluble in alcohol and 
ether ; burns with a bright flame. It was formerly supposed to consist 
entirely of cetine, but recently it has been shown to contain ethers not 
only of palmitic, but also of stearic, myristic, and laurostearic acids ; and 
of the alcohols : lethal, C 13 H 2e O; methal, C 14 H 30 O; ethal, C 16 H 34 0; and 
stethal, C 18 H 38 0. 

G "H" O ) 
Melissyl palmitate — Melissin — l A |V > O — Beeswax — Ceraflava 

(U. S., Br.) — consists mainly of two substances: ceroticacid, which is solu- 
ble in boiling alcohol and melissyl palmitate, insoluble in that liquid, 
united with minute quantities of substances which communicate to the 
wax its color, odor, and unctuousness. Yellow wax melts at 62° — 63°; 
after bleaching, which is brought about by exposure to light, air, and mois- 
ture, it does not fuse below 66°. China wax^ a white substance resem- 
bling spermaceti, is a vegetable product consisting of ceryl cerotate, 
C 3 ,H M O a (C„H J. 



200 



GENERAL MEDICAL CHEMISTRY. 



ALDEHYDES. 

Series C n ELO. 



Formic aldehyde CH 2 0. 

Acetic aldehyde C 2 H 4 0. 

Propionic aldehyde C a H 6 0. 

Butyric aldehyde C 4 H 8 0. 

Isobutyric aldehyde C 4 H 8 0. 



Valerianic aldehyde C 5 H 10 O. 

Caproic aldehyde C 6 H 12 0. 

CEnanthylic aldehyde C 7 H 14 0. 

Caprylic aldehyde C 8 H 16 0. 

Palmitic aldehyde C 16 H 3a O. 



Acetic Aldehyde. 

pun \ 

Acetyl hydride, a V [ . — Although discovered in 1821 by Doebe- 

reiner, and subsequently studied by Liebig, it is only of late years that 
the importance of this body in the organic laboratory has been recognized. 

It is formed in all reactions in which alcohol is deprived of hydrogen 
without simultaneous introduction of oxygen ; whence the name of 
" dehydrogenated alcohol." It is prepared by the process suggested by 
Liebig: a mixture of sulphuric acid, six parts; water, four parts; alcohol, 
four parts, powdered manganese dioxide, six parts, is placed in a capacious 
retort, which is connected with a receiver cooled by a freezing mixture ; 
the retort is warmed very slowly and gently. The distillate, which is a 
mixture of water, alcohol, ether, aldehyde, and other substances, is re- 
distilled from calcium chloride at a temperature not exceeding 50°. This 
second distillate is mixed with two volumes of ether, cooled by a freezing 
mixture, and saturated with dry ammonia gas ; there separate fine, 
colorless crystals of ammonium acetylide, having the composition C 2 H 3 
0,NH 4 , which are washed with ether and dried by exposure to dry 
air ; they are placed in a retort over the water-bath and decomposed 
by the addition of the proper quantity of dilute sulphuric acid ; a clear 
liquid distils over, which is dried by contact with fused calcium chlo- 
ride, and rectified at a temperature not exceeding 35°. 

As thus obtained, aldehyde is a colorless, mobile liquid ; has a strong, 
suffocating odor ; sp.gr. 0.790 at 18°; boils at 21°; soluble in all pro- 
portions in water, alcohol, and ether. If perfectly pure, it may be kept 
unchanged; but if an excess of acid have been used in its preparation, it 
gradually decomposes. When heated to 100°, it is decomposed into 
water and crotonic aldehyde. 

In the presence of nascent hydrogen, aldehyde takes up H 2 and 
regenerates alcohol. Chlorine converts it into acetyl chloride, C 2 H 3 0, 
CI, and other products. Oxidizing agents quickly convert it into acetic 
acid, C 2 H 4 2 . Sulphuric, hydrochloric, and sulphurous acids at the 
ordinary temperature convert it into a solid substance called paraldehyde, 
C 6 H 12 37 (?), which fuses at 10.5°, boils at 124°, and is more soluble in cold 
than in warm water. When heated with potassium hydrate, aldehyde 
becomes brown, a brown resin separates, and the solution contains potas- 
sium formiate and acetate. Gaseous ammonia converts aldehyde into the 
crystalline ammonium acetylide, mentioned above. If a watery solution 
of aldehyde be treated, first with ammonia and then with hydrogen sul- 
phide, a solid, crystalline base, thialdine i C 6 H 13 NS a , separates. Aldehyde 



TEICHLOEALDEHYDE. 201 

also forms crystalline compounds with the alkaline bisulphites. It de- 
composes solutions of silver nitrate, separating the silver in the metallic 
form, and under conditions which cause it to adhere strongly to glass; 
a fact which is utilized in making certain glass-silvering solutions. 

Vapor of aldehyde, when inhaled in a concentrated form, produces as- 
phyxia, even in comparatively small quantity ; when diluted with air it 
is said to act as an anaesthetic. When taken internally it causes sudden 
and deep intoxication, and it is to its presence that the first products of 
the distillation of spirits of inferior quality owe in a great measure their 
rapid, deleterious action. 



Triohloraldehyde, 

Trichlor acetyl hydride ; Chloral — 2 3 tt [■ — discovered in 1832, by 

Liebig. It is one of the final products of the action of chlorine upon al- 
cohol, and is obtained by passing dry chlorine through absolute alcohol 
to saturation ; applying heat toward the end of the reaction, which re- 
quires several hours for its completion. The liquid separates into two 
layers: the lower is removed and shaken with an equal volume of concen- 
trated sulphuric acid and again allowed to separate into two layers; the 
upper is decanted; again mixed with sulphuric acid, from which it is dis- 
tilled; the distillate is treated with quicklime, from which it is again dis- 
tilled, that portion which passes over between 94° and 99° being col- 
lected. It sometimes happens that chloral in contact with sulphuric acid 
is converted into a modification, insoluble in water, known as metachloral; 
when this occurs it is washed with water, dried and heated to 180°, when 
it is converted into the soluble variety, which distils over. 

Chloral is a colorless liquid, unctuous to the touch; has a penetrating 
odor and an acrid, caustic taste; sp. gr. 1.502 at 18°; boils at 94.4°; very 
soluble in water, alcohol, and ether; dissolves chlorine, bromine, iodine, 
sulphur, and phosphorus; its vapor is highly irritating; it distils without 
alteration. 

The metachloral mentioned above is a white, volatile solid, having an 
ethereal odor; insoluble in water, alcohol, and ether; convertible at 180° 
into the liquid chloral, with which it is identical in chemical properties. 

Although chloral has not been obtained by the direct substitution of 
chlorine for hydrogen in aldehyde, its reactions show it to be an aldehyde; 
it forms crystalline compounds with the bisulphites; it reduces solutions 
of silver nitrate in the presence of ammonia; ammonia and hydrogen sul- 
phide form with it a compound similar to thialdine; with nascent hydrogen 
it regenerates aldehyde; oxidizing agfents convert it into trichloracetic 
acid. 

Alkaline solutions decompose chloral with formation of chloroform 
and a formiate: 



C 2 HC1,0 


+ 


KHO = 


-- CHC1 3 


+ 


CH0 2 K 


Chloral. 




Potassium 
hydrate. 


Chloroform. 




Potassium 
formiate. 



With a small quantity of water, chloral forms a solid, crystalline hy- 
drate, heat being at the same time liberated. This hydrate has the com- 



202 GENERAL MEDICAL CHEMISTRY. 

position C 2 HC1 9 0,H 2 0, and its constitution, as well as that of chloral 
itself, is indicated by the formulae: 

CH 8 CC1 9 CCL 

I I I 

CHO CHO CH (OH) a 

Aldehyde. Trichloraldehyde Chloral hydrate, 

(chloral.) 

Chloral hydrate is a white, crystalline solid; fuses at 57°; boils at 98°, 
at which temperature it suffers partial decomposition into chloral and 
water; volatilizes slowly at ordinary temperatures; is very soluble in 
water; neutral in reaction; has an ethereal odor, and a sharp, pungent 
taste. Concentrated sulphuric acid decomposes it with formation of 
chloral and chloralide. Nitric acid converts it into trichloracetic acid. 
When pure it gives no precipitate with silver nitrate solution, and is not 
browned by contact with concentrated sulphuric acid. 

Chloral also combines with alcohol, with elevation of temperature, to 
form a solid, crystalline body — chloral alcoholate. 

CC1 '- CH \0-C a H 6 . 

Action of chloral hydrate upon the economy. — Although it was the ready 
decomposition of chloral into a formiate and chloroform which first sug- 
gested its use as a hypnotic to Liebreich, and although this decomposition 
was at one time believed to occur in the body under the influence of the 
alkaline reaction of the blood, more recent investigations have shown that 
the formation of chloroform from chloral in the blood is, to say the least, 
highly improbable, and that chloral has, in common with many other 
chlorinated derivatives of this series, the property of acting directly upon 
the nerve-centres. 

Neither the urine nor the expired air contain chloroform when chloral 
is taken internally; when taken in large doses, chloral appears in the urine. 
The fact that the action of chloral is prolonged for a longer period than 
that of the other chlorinated derivatives of the fatty series is probably 
due, in a great measure, to its less volatility and less rapid elimination. 

When taken in overdose, chloral acts as a poison, and its use as such 
is rapidly increasing as acquaintance with its powers becomes more widely 
disseminated. 

No chemical antidote is known; the treatment should be directed to 
the removal of any chloral remaining in the stomach by the stomach- 
pump, and to the maintenance or restoration of respiration. 

In fatal cases of poisoning by chloral that substance may be detected 
in the blood, urine, and contents of the stomach by the following method: 
the liquid is rendered strongly alkaline with potassium hydrate; placed 
in a flask, which is warmed to 50° — 60°, and through which a slow current 
of air, heated to the same temperature, is made to pass; the air, after 
bubbling through the liquid, is tested for chloroform by the methods 
described on p. 165. If affirmative results are obtained in this testing, it 
remains to determine whether the chloroform detected existed in the 
fluid tested in its own form, or resulted from the decomposition of chloral; 
to this end a fresh portion of the suspected liquid is rendered acid and 
tested by Hofmann's method, (p. 165); if chloroform be present, the char- 



KETONES OR ACETONES. 203 

acteristic odor of isobenzonitril is observed, while chloral, not being 
decomposed in acid solution, gives a negative result. The nitrate of silver 
test is not available for this purpose in liquids containing chlorides, as 
these, in the presence of even the weakest acids, are partially decomposed 
with liberation of hydrochloric acid. 

The corresponding bromine and iodine compounds are also known. 

CBr 3 

Bromal, — a colorless, oily liquid; sp. gr. 3.34; boils at 172°; 

CHO 
has a persistent, sharp, burning taste, and a penetrating odor; its vapor 
irritates the air-passages and eyes; neutral; soluble in water, alcohol, and 

CBr 8 
ether. By union with water it forms bromal hydrate, ; large, 

CH(OH) 2 
colorless, transparent crystals ; fusible at the temperature of the body; 
soluble in water; has the same taste and odor as bromal; decomposed by 
alkalies into bromoform and a formiate. Produces anaesthesia without 
sleep; very poisonous. 

Iodal and its hydrate have also been obtained. 

The higher aldehydes of this series are obtainable from the corre- 
sponding acids by distilling a mixture of calcium formiate and the calcium 
salt of the corresponding acid: 

(CH0 2 ) 2 Ca + (C 4 H 7 2 ) 2 Ca = 2C0 3 Ca + 2C 4 H 8 

Calcium formiate. Calcium butyrate. Calcium carbonate. Butyric aldehyde. 

As with the acids and alcohols, there exist isomeres of the aldehvdes 
above propylic aldehyde; such are butyral and valeral. Caprylic aldehyde, 
C 8 H 16 is one of the products of decomposition of the fatty oils at high 
temperatures, and, together with acrolein (q. v.), produces the unpleasant 
and deleterious odor observed in engine-rooms, especially on shipboard. 



KETONES OR ACETONES. 

Sekies C„H 2n O. 

Dimethyl ketone, CO/ prr 3 — Acetone — Acetyl methylide — Pyroacetic 

ether — Pyroacetic spirit — is formed as one of the products of the dry dis- 
tillation of the acetates; by the decomposition of the vapor of acetic acid 
at a red heat; by the dry distillation of sugar, tartaric acid, etc.; and in 
a number of other reactions. It is obtained by distilling dry calcium 
acetate in an earthenware retort at a dull red heat; the distillate, col- 
lected in a well-cooled receiver, is freed from water by digestion with 
fused calcium chloride, and rectified; those portions being collected which 
pass over at 60°. It is also formed in large quantity in the preparation 
of aniline, when that substance is distilled with acetate of iron. 

It is a limpid, colorless liquid; sp. gr. 0.7921 at 18°; boils at 56°; 
soluble in water, alcohol, and ether, has a peculiar, ethereal odor, and a 
burning taste; is a good solvent of resins, fats, camphor, gun-cotton; 
readily inflammable. 



204 GENERAL MEDICAL CHEMISTRY. 

It forms crystalline compounds with the alkaline bisulphites. Chlorine 
and bromine, in the presence of alkalies, convert it into chloroform or 
bromoform; chlorine alone produces with acetone a number of chlorinated 
products of substitution. Certain oxidizing agents transform it into a 
mixture of formic and acetic acids; others into oxalic acid. 

Acetone has been found to exist in the blood and urine in certain 
pathological conditions, and notably in diabetes; the peculiar odor ex- 
haled by diabetics is produced by this substance, which has also been 
considered by some authors as being the cause of the respiratory derange- 
ments and coma which frequently occur in the last stages of the disease. 

That acetone exists in the blood in such cases is certain; it is not cer- 
tain, however, that its presence produces the condition designated as 
acetonemia. It can hardly be doubted that the acetone thus existing in 
the blood is indirectly formed from diabetic sugar, and it is probable also 
that a complex acid, known as ethyldiacetic, is formed as an intermediate 
product, and gives rise to acetone by the reaction: 

C 6 H 9 O s Na + 2H 3 = C,H,0 + C 3 H 6 + C0 3 HNa 

Sodium ethyl- Water. Acetone. Alcohol. Hydrosodic 

diacetate. carbonate. 

The higher ketones of this series, propione, butyro?ie, etc., are ob- 
tained by similar methods, from the calcium salts of the corresponding 
acids. Their interest is purely theoretical. 



MONAMINES. 

General methods of preparation. — The primary monamines are formed 
by the action of potassium hydrate upon the corresponding cyanic ether: 

CNO,C 2 H 5 + 2KHO=NH 2 ,C 2 H 5 +C0 3 K 2 

Ethyl cyanate. Potash. Ethylamine. Potassium 

carbonate. 

Or by heating together an alcoholic solution of ammonia and an ether: 
C 2 H 5 I + NH 3 = HI + NH 2 ,C 2 H 6 

Ethyl Ammonia. Hydriodic Ethylamine. 

iodide. acid. 

Or by the action of nascent hydrogen upon the cyanides of the alcoholic 
radicals : 

CN,CH 3 + 2H 3 = NH 2 ,C 2 H 5 . 

Methyl cyanide. Hydrogen. Ethylamine. 

The secondary monamines are formed by the action of the iodides or 
bromides of the alcoholic radicals upon the primary monamines. 

The tertiary monamines are produced by the distillation of the hy- 
drates or iodides of the quaternary ammoniums, or by the action of the 
iodides of the alcoholic radicals upon the secondary monamines 

General properties. — The amines of this series, containing radicals of 
monoatomic alcohols, have the same power of saturation as ammonia. 



MON" AMINES. 203 

They are volatile. The alkalinity and solubility in water of the primary 
nionamines are greater than those of the secondary, and those of the sec- 
ondary greater than those of the tertiary. Their chlorides form sparingly 
soluble compounds with platinic chloride, similar to that formed with the 
same salt by ammonium chloride. Nitrous acid decomposes the mona- 
mines, with regeneration of the corresponding alcohol: 

NH 2 ,C 2 H 5 + N0 2 H = C 2 H 5 HO + H 2 + N 2 . 

Ethylamine. Nitrous Ethylic Water. Nitrogen, 

acid. alcohol. 

With the secondary and tertiary monamines the same reagent produces 
mVroso-compounds, in which an atom of hydrogen is replaced by the group 
(NO)'. 

The three classes of monamines may be separated by the action of ethyl 
oxalate, which forms with the primary a solid compound, and with the 
secondary a liquid, while the tertiary remains free. 

There are but few of the monamines of this series which are of practi- 
cal importance. 

Methylamine — Methylia — tt 3 [• N — is obtained by decomposing 

methyl cyanate by potash, and directing the vapors through dilute hydro- 
chloric acid; the methyl ammonium chloride thus obtained is decomposed 
by quicklime, and the methylamine collected over mercury. 

It is a colorless gas; has a fishy, ammoniacal odor; liquefies a few de- 
grees below 0°; inflammable; is the most soluble gas known; one volume 
of water dissolves 1,154 volumes of methylamine at 12.5°, and 959 volumes 
at 25°; its solution is strongly alkaline and caustic, and has the odor of the 
gas. Its salts are soluble in boiling alcohol. In solution it is distinguish- 
able from ammonia and from ethylamine by its failure to form a precipitate 
with protochloride of molybdenum, and by the formation of a reddish pre- 
cipitate, insoluble in excess, with molybdenum bichloride. Its chloro- 
platinate is yellow, and soluble in boiling water. 

Dimethylamine — Dimethylia — ' *h I N — is a liquid below 8°, at 

which temperature it boils; has an ammoniacal odor; is quite soluble in 
water; is formed by the action of methyl iodide on ammonia. 

Trimethylamine — Trimethylia—(CH^)J$ — is formed with methyl- 
amine and dimethylamine, by the action of methyl iodide upon ammonia, 
by the series of reactions; 

H 3 N + CH,I = (CH 3 )H.,N + HI. 
(CH 3 )H 2 N + CH 3 I = (CH,) 2 HN + HI. 
(CH 3 ) 2 HN + CH 3 I = (CH 3 ) 3 N + HI. 

It is also formed as a product of decomposition of many organic sub- 
stances, and exists widely disseminated in nature. It is one of the pro- 
ducts of the action of potash on many vegetable substances, alkaloids, etc., 
of the putrefaction of fish and starch-paste; it occurs in cod-liver-oil, in 
ergot, in chenopodium, in the flowers of many plants, in yeast, in guano, 
in herring-pickle, in human urine, and in the blood of the calf. It is usu- 
ually obtained by distillation from the pickle in which fish has been pre- 
served. 

At temperatures below its boiling-point, 9°, it is an oily liquid, having 



206 GENERAL MEDICAL CHEMISTRY. 

a disagreeable odor of spoiled fish; alkaline; soluble in water, alcohol, and 

ether; inflammable. It combines with acids to form salts of trimethyl- 

ammonium, which are crystallizable. 

It has frequently been mistaken by writers upon materia medica for 

(0 H ) ) 
its isomere propylamine, ^ 3 t| [• N, which differs from it in odor and in 

boiling at 50°. Its chloride, under the names chloride of propylamia, of 
secalia, ofsecalin, has been used in the treatment of gout and of rheumatism. 

Tetramethyl ammonium hydrate — (CH 8 ) 4 N,OH. — This sub- 
stance, whose constitution is similar to that of ammonium hydrate, is 
obtained by decomposing the corresponding iodide, (CH 3 ) 4 NI, formed by 
the action of methyl iodide upon trimethylamine. It is a crystalline 
solid, deliquescent, very soluble in water; caustic; not volatile without 
decomposition; it attracts carbon dioxide from the air, and combines with 
acids to form crystallizable salts. 

The iodide is said to exert an action upon the economy similar to that 
of curare. 

Ethylamine — Mhylia — ' a rf [■ N — is obtained by the action of 

potash upon ethyl cyanate. It is a light, colorless, mobile liquid; boils 
at 18.7°; has a strong odor like that of ammonia; burns with a bluish 
flame; soluble in all proportions in water, alcohol, and ether. It expels 
ammonia from its salts, combining itself with the acid; its salts are for 
the most part crystallizable, and are soluble in absolute alcohol. With 
chlorine, bromine, and iodine it forms products of substitution contain- 
ing two atoms of the halogen. It forms precipitates in solutions of most 
of the metallic salts, and behaves like ammonia, with solutions of cupric 
salts. The precipitate which it forms in solutions of the alumina salts is 
soluble in an excess of ethylamine. 

Diethylamine — Diethylia — ^ 2 V| [■ N — is an inflammable, color- 
less liquid, very soluble in water; boiling at 57°; having an ammoniacal 
odor, and resembling ethylamine in most of its reactions. 

Triethylamine — Triethylia — (C 2 H & ) S N — is a colorless liquid, lighter 
than water, in which it is sparingly soluble; boiling at 91°; having an 
ammoniacal odor and an alkaline reaction. 

Tetrethyl ammonium hydrate, (C 2 H B ) 4 N,OH — is a crystalline 
solid, very deliquescent; soluble in water, and powerfully basic. 

Choline ; neurine, ,p J Qjly \ N,OH. — This interesting compound 

is a quaternary monammonium hydrate, containing three methyl groups, 
and one ethylene hydroxide group. It has not as yet been found to exist 
free in the animal body, but only as a constituent of those important 
elements of nerve-tissue, the lecithins (q. v.). It was first obtained from 
bile, but is best prepared from the yolks of eggs. 

It appears as a thick syrup, soluble in water and in alcohol, and 
strongly alkaline in reaction. Even in dilute aqueous solution it prevents 
the coagulation of albumin and redissolves coagulated albumin and 
fibrin. It is a strong base; attracts carbon dioxide from the air; forms 
with hydrochloric acid a salt, soluble in alcohol, which crystallizes in 
plates and needles, very much resembling in appearance those of choles- 
terin. 

Choline has been obtained synthetically by the action of a concen- 



MONAMIDES. 207 

trated solution of trimethylamine upon ethylene oxide, or upon ethylene 
chlorhydrate. When heated, it splits up into glycol and trimethylamine. 

By partial oxidation a solid, crystalline base, known as oxyneurine, 
oxycholine, or betain, is formed; in this substance, which has also been 
obtained by synthesis, the group C 2 H 4 OH is replaced by C 3 H 2 0,OH. 

Choline is isomeric with amanitine, and betai'n with muscarine; 
poisonous alkaloids obtained from species of Agaricus. 

Besides the amines here considered, many containing the higher alco- 
holic radicals have been obtained. There are also amines containing two 
or more different alcoholic radicals, such as methyl-ethyl-amylamine, 
CH 3 
C,H 5 [ N. 

MONAMIDES. 

General methods of preparation. — The primary monamides, contain- 
ing radicals of the acids of the acetic series, are formed: 
First. — By the action of heat upon an ammoniacal salt: 

Ammonium acetate. Water. Acetamide, 

Second. — By the action of a compound ether upon ammonia: 

Ethyl acetate. Ammonia. Acetamide. Alcohol. 

Third. — By the action of the chloride of an acid radical upon dry 
ammonia: 

(CAO ci;i^.(l^)- N ?if+ (CA0 ^}N 

Acetyl chloride. Ammonia. Ammonium Acetamide. 

chloride. 

The secondary monamides of the same class are obtained: First, by 
the action of the chlorides of acid radicals upon the primary amides: 

<W } N +«Wg J = (C,H 3 0), I N + H J 

Acetamide. Acetyl chloride. Diacetamide. Hydrochloric 

acid. 

Second. — By the action of hydrochloric acid upon the primary mona- 
mides at high temperatures: 

2 ((^| N) + H (=( C,H 1 0) f | N+ NH 1 J 

Acetamide. Hydrochlorio Diacetamide. Ammonium 

acid. chloride. 



208 GENEKAL MEDICAL CHEMISTRY. 

The tertiary monamides of this series of radicals have been but im- 
perfectly studied; some of them have been obtained by the action of 
the chlorides of acid radicals upon metallic derivatives of the secondary 
amides. 

General properties. — The primary monamides containing radicals of 
the fatty acids are solid, crystallizable, neutral in reaction, volatile with- 
out decomposition, mostly soluble in alcohol and ether, and mostly capa- 
ble of uniting with acids to form compounds similar in constitution to the 
ammoniacal salts. They are capable of uniting with water to form the 
ammoniacal salt of the corresponding acid, and with the alkaline hydrates 
to form the metallic salt of the corresponding acid, and ammonia. The 
secondary monamides, containing two radicals of the fatty series, are acid 
in reaction, and their remaining atom of extra-radical hydrogen may be re- 
placed by an electro-positive atom. 

Formamide, * J !■ N — is a colorless liquid ; soluble in water and in 

alcohol; boils at 192°; formed by the action of ethyl formiate upon dry 
ammonia. 

Acetamide, ^ 2 3 J !■ N — is obtained by heating, under pressure, 

a mixture of ethyl acetate and aqua ammonite, and purifying by distilla- 
tion. It is a solid, crystalline substance, very soluble in water, alcohol, 
and ether; fuses at 78°; boils at 221°; has a sweetish, cooling taste, and 
an odor of mice. Boiling potassium hydrate solution decomposes it into 
potassium acetate and ammonia. Phosphoric anhydride deprives it of the 
elements of water, and forms with it acetonitrile or methyl cyanide. 

There exist also amides corresponding to monochlor acetic and tri- 
chloracetic acids. 



AMIDO-ACIDS OF THE FATTY SERIES. 

Amido-acetic acid — Glycocol — Sugar of gelatin — Glycolamic acid 
CH 2 ,NH a 

— Glycine — | . — This interesting body was first obtained by the 

COOH 
action of sulphuric acid upon gelatin. It is best prepared by acting 
upon glue with caustic potassa, ammonia being liberated; sulphuric acid 
is then added, and the crystals of potassium sulphate separated; the liquid 
is evaporated, the residue dissolved in alcohol, from which solution the 
glycocol is allowed to crystallize. 

It may also be obtained synthetically by a method which indicates its 
constitution — by the action of ammonia upon chloracetic acid. 

CH 2 01 H\ CH 8 NH a -tt 

I + H— N =| + ft 

COOH H/ COOH U1 

Chloracetic Ammonia. Amidoacetic Hydrochloric 

acid. acid. acid. 

It may be obtained from ox-bile, in which it exists as the salt of a con- 
jugate acid; from uric acid by the action of hydriodic acid; and by the 
union of formic aldehyde, hydrocyanic acid, and water. It is isomeric 
with glycolamide. 



AMIDOACIDS OF THE FATTY SERIES. 209 

It has been found to exist free in animal nature only in the muscle of 
the scallop, and, when taken internally, its constituents are eliminated as 
urea. In combination it exists in the gelatinoids, and with cholic acid 
as sodium glycocholate (q. v.) in the bile; it is one of the products of de- 
composition of glycocholic acid, hyoglycocholic acid, and hippuric acid by 
dilute acids and by alkalies, and of the decomposition of tissues contain- 
ing gelatinoids. 

It appears as large, colorless, transparent crystals; has a sweet taste; 
melts at 170°; decomposes at higher temperatures; sparingly soluble in 
cold water; much more soluble in warm water; insoluble in absolute 
alcohol and in ether; acid in reaction. 

It combines with acids to form crystalline compounds, which are de- 
composed at the temperature of boiling water; hot sulphuric acid car- 
bonizes it; nitric acid converts it into glycolic acid (q. v.); with hydro- 
chloric acid it forms a chloride; heated under pressure with benzoic acid 
it forms hippuric acid. Its acid function is more marked; it expels car- 
bonic and acetic acids from calcium carbonate and plumbic acetate. The 
presence of a small quantity of glycocol prevents the precipitation of 
cupric hydrate from cupric sulphate solution by potassium hydrate; the 
solution becomes dark blue, does not yield cuprous hydrate on boiling, 
and precipitates crystalline needles of copper glycolamate on the addition 
of alcohol to the cold solution. With ferric chloride it gives an intense 
red solution, whose color is discharged by acids, and reappears on neu- 
tralization. With phenol and sodium hypochlorite it gives a blue color, 
as does ammonia. By oxidation with potassium permanganate in alka- 
line solution it yields carbon dioxide, oxalic, carbonic, and oxamic acids, 
and water. It also forms crystalline compounds, with many salts and 
ethers. Methyl glycolamate is isomeric with sarcosine: 

CH 2 NH U " CH 2 NH 2 CH 2 NH(CH 3 ) 

COOH COOCH3 COOH 

Glycocol Methyl- Sarcosine 

(amido-acetic acid). glycolamate. (methyl-glycocol). 

CH 2 [NH(CH 3 )] 
Methyl-glyeocol — Sarcosine | — This substance, which 

COOH 
is isomeric with alanine and with lactamide (q. v.), does not exist as such 
in animal nature, but has been obtained from creatine (q. v.) by the action 
of barium hydrate: 

C 4 H 9 N 3 2 + H a O = C 3 H,NO a + CON 2 H 4 

Creatine. Water. Sarcosine. Urea. 

Urea being formed at the same time, and decomposed by the further ac- 
tion of the barium hydrate into ammonia and barium carbonate. 

Its constitution is indicated by its synthetic formation from chlor- 
acetic acid and methylamine: 

0H 2 C1 0H a \ CH,[NH(0H,)] H 

+ H-N I + g 



i 



OOH H/ COOH 

irace 
tcid. 

14 



Chloracetic Methylamine. Sarcosine. Hydrochloric 

acid. acid. 



210 GENERAL MEDICAL CHEMISTRY. 

It crystallizes in colorless, transparent prisms; very soluble in water; 
sparingly soluble in alcohol and ether. Its aqueous solution is not acid, 
and has a sweetish taste; it unites with acids to form crystalline salts, 
but does not form metallic salts. It is capable of combining with cyan- 
amide to form creatine. 



Biliary Acids. 

The bile of most animals contains the sodium salts of two amido-acids 
of complex constitution. These acids may be decomposed into a non- 
nitrogenized acid (cholic acid), and either an amido-acid (glycocol), or an 
amido-sulphurous acid (taurine). The following biliary acids have been 
described: 

Glycocholic acid, C 26 H iS N0 6 — (sometimes designated as Acide cho- 
lique, Cholsdure, Cholic acid, especially by French and German writers, 
who retain the names given it by Gmelin, but which had been previously 
applied to another substance by Demarcay.) It exists as its sodium salt 
in the bile of the herbivora, and in much smaller proportion in that of the 
carnivora ; it exists in small quantity in human blood and urine in icterus; 
in human bile its quantity varies with the diet. 

It is best obtained from ox-bile; this is evaporated to one-fourth of 
its original volume, the residue is ground up with animal charcoal, and 
dried at 100°; the dry mass, while still hot, is broken up and introduced 
into a flask, in which it is digested with absolute alcohol, with repeated 
agitation for some days; the colorless, filtered alcoholic solution is par- 
tially evaporated, but not to the extent of becoming syrupy, then mixed 
with an excess of anhydrous ether, which, if the reagents were free from 
water, causes the immediate separation of a crystalline precipitate of the 
mixed biliary salts. If the alcohol or ether used contain water, the pre- 
cipitate is at first resinous and only becomes crystalline after standing, or 
does not become crystalline if the proportion of water be too great. The 
crystalline deposit is collected upon a filter, washed with ether and dis- 
solved in a small quantity of water ; to the aqueous solution a small 
quantity of ether is added, and then enough dilute sulphuric acid to ren- 
der the mixture permanently cloudy; the glycocholic acid gradually crys- 
tallizes out, and may be further purified by solution in alcohol, and 
precipitation with a great excess of ether. 

Glycocholic acid forms brilliant, colorless, transparent needles, which 
are sparingly soluble in cold water, readily soluble in warm water and in 
alcohol, almost insoluble in ether. The watery solution is acid in reac- 
tion, and tastes at first sweet, afterward intensely bitter; its alcoholic solu- 
tion exerts a right-handed polarization [«•]„ = +29°; when evaporated 
it leaves the acid in a resinous form. 

When heated with potash, baryta, or dilute sulphuric or hydrochloric 
acid, it is decomposed into cholic acid and glycocol: 

C„H„N0 6 + H,0 = M H„0. + C,H s NO, 

Glycocholic acid. "Water. Cholic acid. Glycocol. 

Glycocholic acid dissolves unchanged in cold concentrated sulphuric 
acid, and is precipitated on dilution of the solution with water; if the 
mixture be warmed the bile acid is decomposed, and there separate oily 



BILIARY ACIDS. 211 

drops of eJtoloiilc acid, C 2e H 41 X0 5 , an acid substance, differing from gly- 
cocholic acid by — H 2 0. When allowed to remain long in contact with 
concentrated sulphuric acid, glycocholic acid is converted into a colorless, 
resinous mass, which slowly forms a saffron-yellow solution with the 
mineral acid, which turns flame-red when warmed, and which, on dilution, 
deposits a flocculent material which is colorless, greenish, or brownish, 
according to the temperature at which it is formed. Glycocholic acid, 
altered by contact with concentrated sulphuric acid, absorbs oxygen when 
exposed to the air, and turns red, then blue, and finally brown after a few 
days. 

Of the salts of glycocholic acid, sodium glycocholate, C 26 H 42 NO e Xa, 
exists in the bile; it crystallizes in stellate needles, very soluble in water, 
less so in absolute alcohol, and insoluble in ether; its alcoholic solution 
exerts right-handed polarization [c^] D = +25.7°. 

Lead glycocholate, (C 26 H 42 N0 6 ) 2 Pb (?) — is formed as a white, floccu- 
lent precipitate, when solution of lead subacetate is added to a solution 
of a glycocholate or of glycocholic acid; with the neutral acetate the pre- 
cipitation does not occur in the presence of an excess of acetic acid. It 
is soluble in alcohol, and in an excess of lead acetate solution. 

The glycocholates of the alkaline earths are soluble in water. Gly- 
cocholic acid and the glycocholates react with Pettenkofer's test (see 
below). 

Glycocholic acid forms compounds with the alkaloids, some of which 
are crystalline, others amorphous; they are for the most part very sparingly 
soluble in water, but readily soluble in solutions of the biliary salts and 
in bile. 

Taurocholic acid, C 26 H 45 N0 7 S (called by Streckei choleic acid), 
exists as its sodium salt in the bile of man and of the carnivora, and in 
much less abundance in that of the herbivora ; in the bile of the dog it 
seems to be unaccompanied by any other biliary acid. It may be obtained 
from dog's bile by a modification of the method described under glyco- 
cholic acid; the watery solution is not treated with sulphuric acid, as in 
the preparation of that acid, but with solution of basic lead acetate and 
ammonia. The precipitate so formed is extracted with boiling alcohol, 
the solution filtered hot and treated with hydrogen sulphide ; the clear 
liquid, filtered from the precipitated lead sulphide, is evaporated to a small 
bulk and treated with a large excess of ether; the acid is precipitated in 
the resinous form, but, after standing for a varying period, assumes the 
crystalline form. 

When carefully prepared it forms silky, crystalline needles, which, 
when exposed to the air, deliquesce rapidly, and which, even under abso- 
lute ether, are gradually converted into a transparent, amorphous, resinous 
mass. It is soluble in water and in alcohol, insoluble in ether; its aqueous 
solution is very bitter; in alcholic solution it deviates the plane of polar- 
ization to the right, [a] D =24.5°; its solutions are acid in reaction. 

Taurocholic acid is very readily decomposed by heating with barium 
hydrate, with dilute acids, and even by evaporation of its solution, into 
cholic acid and taurine. 

C,.H, 6 NO,S + H,0 = C„H„0. + CJH,NO s S 

Taurocholic acid. Water. Cholic acid. Taurine. 

The same decomposition occurs in the presence of putrefying material 
and in the intestine. Taurocholic acid has not been found to accompany 
glycocholic in the urine of icteric patients. 



212 GENERAL MEDICAL CHEMISTRY. 

The taurocholates are neutral in reaction; those of the alkaline metals 
are soluble in alcohol and in water; and by long contact with ether they 
assume the crystalline form. They may be separated from the glycocho- 
lates in watery solution, either: 1st, by dilute sulphuric acid in the 
presence of a small quantity of ether, which precipitates glycocholic acid 
alone; or 2d, by adding neutral lead acetate to the solution of the mixed 
salts, which must be neutral in reaction, lead glycocholate is precipitated 
and separated by nitration; to the mother liquor basic lead acetate and 
ammonia are added, when lead taurocholate is precipitated. The acids 
are obtained from the hot alcoholic solutions of the lead salts by decompo- 
sition with hydrogen sulphide, filtration, concentration, and precipitation 
by ether. 

Solutions of the taurocholates, like those of the glycocholates, have 
the power of dissolving cholesterin and of emulsifying the fats; they 
also form with the salts of the alkaloids compounds which are insoluble 
in water, but soluble in an excess of the biliary salt. The taurocholate of 
morphine is crystallizable. They react with Pettenkofer's test. 

Hyoglycocholic acid, C 27 H 43 N0 5 and hyotaurocholic acid, C 27 H 45 NO s 
S (?) are conjugate acids of hyocholic acid, C 25 H 40 O 4 , and glycocol and 
taurine, which exist in the bile of the pig. Chenotaurocholic acid, a 
conjugate acid of taurine and chenocholic acid, C 27 H 44 4 , is obtained from 
the bile of the goose. 

Cholic acid, C 24 H 40 O 5 (called by Strecker, cholalic acid), is a product 
of decomposition of glyco- and taurocholic acids, obtained as indicated 
above. It also occurs, as the result of a similar decomposition, in the 
intestines and fasces of both herbivora and carnivora. It forms large, 
clear, deliquescent crystals; sparingly soluble" in water, readily soluble in 
alcohol and ether; intensely bitter in taste, with a sweetish aftertaste; 
in alcoholic solution it is dextrogyric [a] D =35°. The alkaline cholates are 
crystallizable and readily soluble in water, the others difficultly soluble. 
Cholic acid and the cholates respond to Pettenkofer's test. 

By boiling with acids or by continued heating to 200°, cholic acid 
loses the elements of water, and is transformed into dyslysin, C 24 H 36 3 , a 
neutral, resinous material, insoluble in water and alcohol, sparingly solu- 
ble in ether. 

Tests for the biliary acids — The PettenTcofer reaction. — All of the 
biliary acids, and the cholic acid and dyslysin obtained by their decom- 
position, have the property of forming a yellow solution with concen- 
trated sulphuric acid, the color of which rapidly increases in intensity, 
and which exhibits a green fluorescence. Their watery solutions also, 
when treated with a small quantity of cane-sugar and with concentrated 
sulphuric acid, so added that the mixture acquires a temperature of 70° 
but does not become heated much beyond that point, develop a beauti- 
ful cherry-red color, which gradually changes to dark reddish purple. 
Although this reaction is observed in the presence of very small quanti- 
ties of the biliary acids, it loses its value, unless applied as directed below, 
from the fact that many other substances give the same reaction, either 
with sulphuric acid alone, or in the presence of cane-sugar. Among these 
substances are many which exist naturally in animal fluids, or which may 
be introduced with the food or as medicines; such are cholesterin, the 
albuminoids, lecithin, oleic acid, cerebrin, phenol, turpentine, tannic acid, 
salicylic acid, morphine, codeine, many oils and fats, cod-liver oil, etc. It 
has been suggested that a distinction could be made between the color 
produced by the Pettenkofer test with the biliary acids, and those pro- 



BILIARY ACIDS. 213 

duced by the same test with other substances, by spectroscopic observa- 
tion; the test with biliary acids in watery solution exhibiting a single 
dark and broad absorption-band, extending from E to midway between 
D and E; the same test with the acids in alcoholic solution shows two 
bands, one similar to that already described, and a second narrower and 
fainter at F. But while this spectrum differs from those observed in the 
purple solutions obtained with many other bodies under similar con- 
ditions, it does not differ sufficiently from that obtained with the mor- 
phine salts and with other substances, to render it a safe method for con- 
trolling the test. 

The following method of applying Pettenkofer's test to the urine and 
other fluids removes, we believe, every source of error. The urine, etc., 
is first evaporated to dryness at the temperature of the water-bath, a 
small quantity of coarse animal charcoal having been added; the residue 
is extracted with absolute alcohol, the alcoholic liquid filtered, partially 
evaporated, and treated with ten times its bulk of absolute ether; after 
standing an hour or two, any precipitate which may have formed is col- 
lected upon a small filter, washed with ether, and dissolved in a small 
quantity of water; this aqueous solution is placed in a test-tube, a drop 
or two of a strong aqueous solution of cane-sugar (sugar, 1; water, -1), and 
then pure concentrated sulphuric acid, are added; the addition of the acid 
being so regulated, and the test-tube dipped from time to time in cold 
water, that the temperature shall be from 60° — 75°. In the presence of 
biliary acids the mixture usually becomes turbid at first, and then turns 
cherry-red and finally purple, the intensity of the color varying with the 
amount of biliary acid present. 

Physiological chemistry of the biliary acids. — That these substances 
do not normally pre-exist in the blood, and are consequently formed in 
the liver, and that they are not reabsorbed from the intestine unchanged, 
is shown by the experiments of Kunde, Molesehott, and Feltz and Ritter. 
The last-named have found that solutions of the biliary salts, injected 
into the circulation in small quantity, cause a diminution in the frequency 
of the pulse and of the respiratory movements, a lowering of the tempera- 
ture and arterial tension, and disintegration of the blood-corpuscles; in 
large doses (2 — 4 grams for a dog) they produce the same effects to a more 
marked degree; epileptiform convulsions, black and bloody urine, and 
death, more or less rapidly. These effects do not follow the injection of 
the products of decomposition of the biliary acids, except cholic acid, and 
in that case the symptoms are much less well marked. Nor are the bil- 
iary acids discharged unaltered with the faeces; they are decomposed in 
the intestine. The extract, suitably purified, of the contents of the upper 
part of the small intestine, gives a well-marked reaction with Petten- 
kofer's test; while a similar extract of the contents of the lower part of 
the large intestine, or of the faeces, fail to give the reaction, and conse- 
quently are free from glyco- or taurocholic, cholic acid, or dyslysin; the 
faeces have, moreover, not been found to contain either taurine or glyco- 
col. During the processes, at present but imperfectly understood, which 
take place in the intestine, the bile-acids are undoubtedly decomposed 
into cholic acid and taurine or glycocol, which are subsequently reab- 
sorbed, either as such, or after having been subjected to further decom- 
position; and as a consequence of their decomposition they probably 
have some influence upon intestinal digestion. 

The biliary salts are precipitated from their aqueous solution, or from 
bile, by fresh gastric juice from the same animal; but they are not so 



214 



GENEKAL MEDICAL CHEMISTRY. 



precipitated if the gastric juice contain peptones. The proportion of bil- 
iary salts in human bile seems to vary considerably, as shown by the fol- 



lowing" analyses: 





I. 


n. 


in. 

2.21 
4.73 

10.79 

1.08 

82.27 
17.73 


IV. v. 


VI. 


VII. 


VIII. 


IX. 




2.66 
0.16 
0.32 

7.22 


2.98 
0.26) 
0.92 j" 

9.14 


1.45 .... 
„ A ( 0.25 


2.48 
0.25 
0.05 
0.75 
2.09 
0.82 
0.46? 
90.88 
9.12 


1.29 
0.34 
0.36 
1.93 
0.44 
1.63 
1.46? 
91.08 
8.92 


i*.57 
4.90 
1.46 


1.29 


Oholesterin 


0.35 


Fats 


3.09 
5.65 

0.63 

89.81 
10.19 


]0.04 

\ 4.48 
0.64 
3.86 


0.75 


Taurocholate of sodium, [ 
Glycocholate of sodium, j * * 
Soaps 


0.87 
3.03 
1.39 


Water 


0.65j 0.77 
86.00i85.92 






14.0014.08 





I. Frerichs: Bile from man, set. 18, killed by a fall. II. Frericha: Male, sat. 22, died 
of a wound. III. Gorup-Besanez : Male, aet. 49, decapitated. IV. Gorup-Besanez : 
Female, set. 29, decapitated. V. Jacobsen : Male, biliary fistula. VI., VII. Trif'anow- 
ski : Males. VIII. Socoloff : Mean of six analyses of human bile. IX. Hoppe-Seyler : 
Mean of five analyses of bile from subjects with healthy livers. 

Pathologically, the biliary acids may be detected in the blood and 
urine in icterus and acute atrophy of the liver, although by no means as 
frequently as the biliary coloring matters. 

CH— CH 2 (NH 2 ) 
Amidopropionic Acid — Alanine, I . — Isomeric with 

COOH 
sarcosine and with lactamide; does not exist, so far as is known at present, 
in nature. It is obtained by the action of alcoholic ammonia upon bromo- 
proprionic acid: 



CH 2 Br CH,(NH 2 ) 

CH, + 2IH— N)=CH 



COOH 

Bromopropi- 
onic acid. 



\H/ 



') 



Ammonia. 



COOH 

Amidopropi- 
onic acid. 



+ BrNH 4 . 



Ammonium 
bromide. 



It may also be prepared by starting from lactic acid, from which it differs 
by containing NH 2 in place of OH. 

It crystallizes in large, oblique, rhombic prisms; very soluble in water; 
sparingly soluble in alcohol; insoluble in ether. Its aqueous solution is 
neutral and sweet. Nitrous acid converts it into lactic acid, nitrogen, and 
water. It dissolves in acids without neutralizing them, but yet, in cer- 
tain cases, with the formation of crystalline compounds. Its barium, lead, 
copper, and silver salts are soluble and crystalline. 

Amidobutyric Acid — JButalanine, C 4 H 9 N0 2 , and Amidovaleri- 
anic acid, C 5 H n N0 2 — are only of theoretic interest at present. The 
latter has been found in the tissue of the pancreas and among the pro- 
ducts of the action of pancreatic juice upon albumin. They are both 
among the products of the decomposition of albumin by caustic baryta. 

CH 2 -C 3 H-CH 2 (NH 2 ) 

Amidocaproic Acid — Leucine — | =C 6 H 13 NO, 

COOH 
— was first obtained by Proust as a product of putrefaction of gluten in 



LEUCINE. 215 

presence of water. It has since been found to exist widely distributed in 
animal nature; it has been obtained- from the normal spleen, pancreas, sali- 
vary, lymphatic, thymus, and thyroid glands, lungs, and liver. Pathologi- 
cally, its quantity in the liver is much increased in diseases of that organ, 
and in typhus and variola; in the bile in typhus, in the blood in leucocy- 
thsemia, and in yellow atrophy of the liver; in the urine in yellow atrophy 
of the liver, in typhus, and in variola; in choleraic discharges from the 
intestine, in pus, in the fluids of dropsy, and of atheromatous cysts. In 
these situations it is usually accompanied by tyrosine (q. v.). It is much 
more abundant in the tissues of the lower forms of animal life, and has 
a*so been found in vegetable tissues. 

It is formed by the decomposition of nitrogenized animal and vege- 
table substances by heating with strong alkalies or dilute acids; by the 
decomposition of elastic tissues it is formed with a small quantity of 
tyrosine; by that of gelatinoid materials, leucine and glycine are obtained; 
by that of albuminoids, leucine and a small, but variable, quantity of tyro- 
sine are formed; and that of epidermic tissues yields leucine and tyrosine. 
It is also one of the products of the putrefaction of animal and vegetable 
albuminoids, and of the action of pancreatic juice upon fibrin. It has also 
been formed synthetically by the action of ammonia upon bromocaproic 
acid in the same way that alanine is formed from bromopropionic acid 
(see above). 

It may be obtained by a variety of methods, the most advantageous of 
which consists in boiling one part of horn-shavings with four parts of sul- 
phuric acid and twelve parts of water, for thirty-six hours, renewing the 
water as it evaporates; the acid liquid is saturated with milk of lime 
and boiled again for twenty-four hours; it is then filtered through linen, 
a slight excess of sulphuric acid is added, and the liquid again filtered and 
evaporated; tyrosine first crystallizes out and is separated, after which 
leucine separates in crystals, which are purified by recrystallization from a 
small quantity of water, the crystals first formed being rejected as being 
contaminated with tyrosine. The leucine so obtained is further purified 
by solution in hot water, digestion with lead hydrate; filtration, treatment 
with hydrogen sulphide; filtration, treatment with animal charcoal; filtra- 
tion and crystallization. 

Leucine crystallizes from alcohol in soft, pearly plates, lighter than 
water, and somewhat resembling cholesterin; sometimes in round masses 
composed of closely grouped needles radiating from a centre. It is spar- 
ingly soluble in cold water; readily in warm water; almost insoluble in 
cold alcohol and ether; soluble in boiling alcohol, which deposits it on 
cooling; it is odorless and tasteless, and its solutions are neutral. Its sol- 
ubility in water is increased by the presence of acetic acid or of potassium 
acetate. It sublimes at 170° without decomposition; if suddenly heated 
above 180°, it is decomposed into amylamine and carbon dioxide. 

When heated to 140° with hydriodic acid under pressure, it is decom- 
posed into caproic acid and ammonia. Nitrous acid converts it into leucic 
acid, C«H, , water, and nitrogen. It unites with acids to form soluble 
crystalline salts. It also dissolves readily in solutions of alkaline hydrates, 
forming crystalline compounds with the metallic elements. 

The formation of leucine in the body is one of the steps of the trans- 
formation of at least some part of the albuminoids into urea. That leu- 
cine is formed at the expense of the albuminoids by some fermentation- 
like process, there can be no doubt; as it is only discharged in the urine 
in certain exceptional pathological conditions, and as at the same time the 



216 GENERAL MEDICAL CHEMISTRY. 

elimination of urea is greatly diminished, it seems highly probable that 
under normal conditions the nitrogen of leucine finally makes its exit from 
the body as urea, notwithstanding the fact that chemists have hitherto 
been unable to obtain urea from leucine artificially. As to the nature of 
the changes by which leucine is converted into urea in the body, we are 
as yet in the dark. 

When leucine and tyrosine appear in the urine, that fluid is poor in 
urea and usually contains biliary coloring matters; the substitution of 
leucine for urea may be so extensive that the urine contains no urea, and 
contains leucine in such quantity that it crystallizes out spontaneously. 

The presence of smaller quantities of leucine and tyrosine in the 
urine may be detected as follows: the freshly collected urine is treated 
with basic lead acetate, filtered, the filtrate treated with hydrogen sul- 
phide, filtered from the precipitated lead sulphide, and the filtrate evap- 
orated over the water-bath; leucine and tyrosine crystallize; they may 
be separated by extraction of the residue with hot alcohol, which dissolves 
the leucine and leaves the tyrosine. The leucine left by evaporation of 
the alcoholic solution may be recognized by its crystalline form and by 
the following characters : 1st, a small portion is moistened on platinum 
foil with nitric acid, which is then cautiously evaporated; a colorless res- 
idue remains, which, when warmed with caustic soda solution, turns yel- 
low or brown, and by further concentration is converted into oily drops, 
which do not adhere to the platinum (Scherer's test); 2d, a portion 
of the residue is heated in a dry test-tube; it melts into oily drops, and 
the odor of amylamine (odor of ammonia combined with that of fusel oil) 
is observed; 3d, if a boiling mixture of leucine and solution of neutral 
lead acetate be carefully neutralized with ammonia, brilliant crystals of a 
compound of leucine and lead oxide separate; 4th, leucine carefully 
heated in a glass tube open at both ends, to 170°, sublimes without fus- 
ing, and condenses in flocculent shreds, resembling those of sublimed 
zinc oxide. If heated beyond 180°, the decomposition mentioned in 2d 
occurs. 

Tyrosine, C 9 H 11 NO s .- 

A substance which certainly does not belong to this series, and is 
probably an amido-acid of the aromatic series; nevertheless, as its consti- 
tution is still undetermined, and as it is almost universally found to ac- 
company leucine in animal tissues and in the products of their decompo- 
sition, it may be considered in this place. 

The methods of its formation and preparation are given under leu- 
cine. 

It crystallizes from its watery and ammoniacal solutions in silky nee- 
dles, arranged in stellate bundles; very sparingly soluble in cold water; 
almost insoluble in alcohol; more soluble in hot water. When heated it 
turns brown and yields an oily matter having the odor of phenol; when 
heated in small quantities to 270°, it is decomposed into carbon dioxide 
and a white solid, having the composition CgH^NO, which sublimes. It 
combines with both acids and bases. 

It has been found in animal nature in the same situations as leucine. 
When taken into the stomach it is not altered in the economy, but is elim- 
inated in the urine and faeces. 

Tyrosine may be recognized by the following characters : 1st, its crys- 
talline form; 2d, when heated it does not sublime, but gives off an odor 



CREATININE. 217 

resembling that of phenol; 3d, when moistened on platinum foil with 
nitric acid and this carefully evaporated, it dissolves and leaves a deep yel- 
low residue, which, when moistened with sodic hydrate solution, turns 
deep yellowish red and leaves, on evaporation of the soda, a dark brown 
residue (Scherer); 4th, when moistened on a porcelain dish with con- 
centrated sulphuric acid and slightly warmed, it dissolves with a transient 
red color; the solution, diluted with water, neutralized with calcium car- 
bonate and filtered, gives a liquid to which a neutral solution of ferric 
chloride communicates a fine violet color (Piria); 5th, if boiled with a 
solution of acid nitrate of mercury, a pink color is first observed, and later 
a red precipitate (Hoffmann, L. Meyer). 



Creatine, C 4 H 9 N 3 2 +Aq. 

Another complex amido-acid, which occurs as a normal constituent of 
the juices of muscular tissue, voluntary and involuntary, of brain, blood, 
and amniotic fluid. Its existence in the urine is very doubtful. 

It is best obtained from the flesh of the fowl, which contains 0.32 per 
cent,, or from beef-heart, which contains 0.14 per cent., by hashing, 
warming with alcohol and expressing strongly; the alcohol is distilled off, 
the residual liquid precipitated with lead acetate, filtered, treated with 
hydrogen sulphide, again filtered, the filtrate evaporated to a syrup, from 
which the creatine crystallizes. 

It is soluble in boiling water and in alcohol, insoluble in ether; crys- 
tallizes in brilliant, oblique, rhombic prisms; neutral, tasteless, loses aq. 
at 100°; fuses and decomposes at higher temperatures. 

When long heated with water or treated with concentrated acids, it 
loses H 2 0, and is converted into creatinine. Baryta water decomposes it 
into sarcosine and urea. It is not precipitated by silver nitrate, except 
when it is in excess and in presence of a small quantity of potassium 
hydrate; the white precipitate so obtained is soluble in excess of potash, 
from which a jelly separates which turns black, slowly at ordinary tem- 
peratures, rapidly at 100°. A white precipitate, which turns black when 
heated, is also formed when a solution of creatine is similarly treated with 
mercuric chloride and potash. 

Creatin is undoubtedly an intermediate product of disassimilation of 
the albuminoid constituents of the tissues in which it occurs; it is not dis- 
charged as such, but only after decomposition into creatinine and into urea, 
both of which increase in quantity in the urine when creatine is taken. 



Creatinine, C 4 H 7 N 3 0. 

A product of the dehydration of creatine, is a normal and constant 
constituent of the urine and amniotic fluid, and has also been found to 
exist in the blood and muscular tissue. 

It crystallizes in oblique, rhombic prisms, soluble in water and in hot 
alcohol; insoluble in ether. It is a strong base, has an alkaline taste and 
reaction, expels ammonia from the ammoniacal salts, and forms well-defined 
salts, among which is the double chloride of zinc and creatinine (C 4 II 7 
N 3 0) 2 ZnCl 2 , obtained in very sparingly soluble, oblique prismatic crystals, 
when alcoholic solutions of creatinine and zinc chloride are mixed. 



218 GENERAL MEDICAL CHEMISTRY. 

The quantity of creatinine eliminated is slightly greater than that of uric 
acid, 0.6 — 1.3 gram in twenty-four hours; it is not increased by muscular 
exercise, but is diminished in progressive muscular atrophy. It is obtained 
from the urine by precipitation with zinc chloride. 



COMPOUNDS OF THE ALCOHOLIC RADICALS WITH 

OTHER ELEMENTS. 

The organic substances hitherto considered are composed of seven 
elements only: carbon, hydrogen, oxygen, nitrogen, chlorine, bromine, 
and iodine; but compounds of carbon containing every known element have 
been observed to exist in nature, or have been produced artificially. Of 
these quite a number may be considered as containing the radicals of the 
series C n H 2M+1 , which exist in the monoatomic alcohols. These bodies are 
almost exclusively the products of the laboratory, and resemble in consti- 
tution some of the compounds already considered. 

Sulphides. — The compounds of the alcoholic radicals with sulphur 
are the same in constitution as those with oxygen, sulphur taking the 
place of oxygen: 

C 2 H 6 ) ryr C 2 H 5 ) „ C 2 H 5 ) «„ 2 H 5 ) an 

H [ U C 2 H 5 f U H \ b C 2 H 5 f b 

Ethyl hydrate Ethyl oxide Ethyl sulphydrate Ethyl sulphide, 

(alcohol). (ether). (mercoptan). 

Similar compounds have been obtained in which the oxygen is replaced 
by tellurium or by selenium. 

Ethyl sulphydrate, usually known as mercaptan, from its tendency to 
unite with mercury {corpus mercurium captans), is formed in a great 
variety of reactions. It is best prepared by treating alcohol with sul- 
phuric acid, as in the preparation of sulphovinic acid (q. v.), mixing the 
crude product with excess of potash, separating from the crystals of potas- 
sium sulphate, saturating with hydrogen sulphide, and distilling. 

It is a mobile, colorless liquid; sp. gr. 0.8325, at 21°; has an intensely 
disagreeable odor, combined of those of garlic and sulphuretted hydrogen; 
boils at 36.2°; ignites readily and burns with a blue flame; may be readily 
frozen by the cold produced by its own evaporation; neutral in reaction; 
sparingly soluble in water, soluble in all proportions in alcohol and ether; 
dissolves iodine, sulphur, phosphorus. 

Potassium and sodium act with mercaptan as with alcohol, replacing 
the extra-radical hydrogen. In its behavior toward the oxides it more 
closely resembles the acids than the alcohols, being capable even of enter- 
ing into double decomposition to form salts, called sulphethylates or mer- 
captides. Its action with mercuric oxide is characteristic, forming a 
white, crystalline sulphide of ethyl and mercury: 

3 (° 2 h} S ) + H S" = (C, Hg"K + H '° 

Ethyl sulphydrate. Mercuric oxide. Ethyl-mercurial sulphide. Water. 

It forms similar compounds with gold and platinum. 

Ethyl sulphide, a colorless liquid; having a penetrating, disagreeable 
odor of garlic; boiling at 73°; insoluble in water, soluble in alcohol; in- 






COMPOUNDS OF THE ALCOHOLIC RADICALS. 219 

flammable; obtained by the action of ethyl chloride upon potassium sul- 
phide. 

Phosphines, arsines, and stibines are compounds resembling the 
amines in constitution, in which the nitrogen is replaced by phosphorus, 
arsenic, or antimony; like the amines, they may be primary, secondary,, 
or tertiary: 

C,H B ) 
C,H. \ As 
H) 

Ethylamine Ethylphospine Diethyl-arsine Triethyl-stibine 

(primary). (primary). (secondary). (tertiary). 

There also exist compounds containing phosphorus, antimony, or arse- 
nic, which are similar in constitution to the hydrates and salts of ammo- 
nium, and of the compound ammoniums: 

NH 4 I N (CH„) 4 I As (CH,) 4 I 

Ammonium Tetramethyl ammonium Tetramethyl arsenium 

iodide. iodide. iodide. 

Most of these compounds, which are very numerous, are as yet only 
of theoretic interest. One of them, however, is deserving of notice here: 

Dimethyl arsine, CH 3 V As — which may be considered as being the 
H) 
hydride of the radical [As (CH 3 ) 2 ], does not exist as such; there was, how- 
ever, discovered by Cadet, in 1760, a liquid known as the fuming liquor 
of Cadet, or alkarsin, which he obtained by distilling a mixture of potas- 
sium acetate and arsenic trioxide. This liquid was made the subject of 
most successful study by Bunsen, who found that it contained the oxide 
of the above radical, and a substance which ignited on contact with air, 
and which consists of the same radical united to itself 2 [As (CH 3 ) 2 ]. He 
subsequently found that this radical, to which he gave the name of caco- 
clyle (kolkos = evil), was capable of entering into a great number of other 
combinations. Cacodyle and its compounds are all exceedingly poison- 
ous, especially the cyanide, an ethereal liquid, very volatile, the presence 
of whose vapor in inspired air, even in minute traces, produces symptoms 
referable both to arsenic and to hydrocyanic acid. 

Organo-metallic substances are compounds of the alcoholic radi- 
cals with that class of elements usually designated as metallic. They 
are very numerous, usually obtained by the action of the iodide of the 
alcoholic radical upon the metallic element, in an atmosphere of hydrogen. 
They are substances which, although they have been put to no uses in 
the arts or in medicine, have been of great practical service in chemical 
research. As typical of this class of substances we may mention: 

P IT ) 

Zinc-ethyl, A 2 jr b !■ Zn — a substance discovered in 1849, by Frankland. 

It is obtained by heating at 130° in a sealed tube a mixture of perfectly 
dry zinc amalgam with ethyl iodide; the contents of the tube are then 
distilled in an atmosphere of coal-gas, or hydrogen, and the distillate 
collected in a receiver, in which it can be sealed by fusion of the glass 
without contact with air. 



220 



GENERAL MEDICAL CHEMISTRY. 



It is a colorless, transparent, highly refracting liquid; sp. gr. 1.182; 
boils at 118°. On contact with air it ignites and burns with a luminous 
flame, bordered with green, and gives off dense clouds of zinc oxide, a 
property which renders it very dangerous to handle. With carbon dioxide 
it combines to form zinc propionate: 



Zinc ethyl. 



+ 2C0 2 = 

Carbon dioxide. 



(C 3 H 5 0,),Zn. 

Zinc propionate. 



On contact with water it is immediately decomposed into zinc hydrate 
and ethyl hydride. It is chiefly useful as an agent by which the radical 
ethyl can be introduced into organic molecules; thus, by the action of 
zinc ethyl upon acetyl chloride, a compound of acetyl and ethyl is ob- 
tained : 



Zn (C.H.), 

Zinc-ethyl. 



2C 2 H 3 0C1 

Acetyl chloride. 



ZnCl 2 + 

Zinc chloride. 



2(C,H 3 OAH s ) 

Acetyl-ethyl. 



ALLYLIC SERIES. 

The compounds which we have heretofore considered may be derived 
■more or less directly from the saturated hydrocarbons; in the derivatives, 
as in the hydrocarbons, the valences of the carbon atoms are all satisfied, 
and that in the simplest and most complete manner, two neighboring 
atoms of carbon always exchanging a single valence. There exist, how- 
ever, other compounds, containing less hydrogen in proportion to carbon 
than those already considered, and yet resembling them in being mono- 
atomic. These compounds have usually been considered as non-saturated, 
because all the possible valences are not satisfied, and the substances are 
therefore capable of forming products of addition, while the saturated 
compounds can only form products of substitution. 

In this sense the substances composing this series are non-saturated, 
but they are not so in the sense that they contain carbon or other atoms 
whose valences are not satisfied. The following formulae indicate the 
constitution of the substances of this series, and their relation to those 
of the previous one. It will be observed that in the allyl compounds two 
neighboring atoms of carbon exchange two valences: 



CH a 

I 
CEL 



0H a H 
or 

<c,H,y 

H 



CH 

I 
CH 

A 



H 3 OH 



or 



CH S 

I 
CH, 





OH 
or 



CH 3 

I 
CH 2 

COOH 
or 



Propyl hydride Propyl hydrate 
(hydrocarbon). (alcohol). 



Propionyl hydride Propionyl hydrate 
(aldehyde). (acid). 



f 0H.1 
CH S 
CH. 



j ( c 3 h^ (C.h.0^ (c 3 H t oyj ((W 



Propyl 
(radical). 



ALLYLIC SERIES. 



221 



rcH a 

I! 
CH 



1 



CH, 

II 
CH 



H 5 

or 



C 3 H £ 
C.H. 



Diallyl 
(hydrocarbon) . 



CH 2 OH 



or 



OH, 

II 
CH 



OH 



or 



CH 2 

II 
CH 

COOH 
or 



r CH 2 ^ 

II 
CH 

CH„ 



(C 3 H 5 ^ (0.H,O^ (0 3 H 3 O^ o ?0A)f 



Allyl hydrate 
(alcohol). 



Acrolein 
(aldehyde) . 



Acrylic acid 
(acid). 



Allyl 
(radical). 



C H ) 
Diallyl, pVr 5 [ — formerly known as allyl, is obtained by the action 

of sodium upon allyl iodide, and is not, as its empirical formula would 
seem to indicate, a superior homologue of acetylene and allylene (q. v.). 

It is a colorless liquid, having a peculiar odor, somewhat resembling 
that of horseradish; boils at 59°; sp. gr. 0.684: at 14°; burns with a lumi- 
nous flame. 

Allyl iodide, C 3 H 5 I — is a colorless liquid, having an ethereal, alli- 
aceous odor; boiling at 101°; sp. gr. 1.789 at 16°; obtained by the action 
of phosphorus triiodide upon either allylic alcohol or glycerin. 

Allyl hydrate — Allylic alcohol — 3 ^t !■ O — may be obtained by a 

variety of methods: 

First. — By the action of silver oxalate upon allyl iodide, allyl oxalate 
is formed; this is then decomposed with ammonia, and oxamide and allyl 
hydrate are obtained. 

Second.— By the action of sodium upon dichlorhydrine in ethereal 
solution. 

Third. — The best process consists in heating four parts of glycerin 
with one part of crystallized oxalic acid. In the first stage of the oper- 
ation carbon dioxide is given off abundantly; as the temperature rises 
the formation of carbon dioxide diminishes, and again increases at about 
190°, when allyl alcohol begins to be formed; at this time the receiver 
connected with the retort, in which the mixture is heated, is changed^ 
and the heat increased to about 260°. The product, which is a mixture 
of allyl alcohol with allyl formiate, formic acid, acrolein, and glycerin, is 
purified by agitation with sodium carbonate and with caustic potassa, 
after which it is rectified, and finally distilled from quicklime. 

Allylic alcohol is a colorless, mobile liquid; solidifies at —54°; boils 
at 97°; sp. gr. 0.8507 at 25°; soluble in water; has an odor resembling 
the combined odors of alcohol and essence of mustard; burns with a 
luminous flame. 

Allyl alcohol is isomeric with propylic aldehyde and with acetone. 
Being an unsaturated compound, it is capable of forming products of 
addition with chlorine, bromine, and iodine, etc., which are isomeric or 
identical with products of substitution obtained by the action of the same 
elements upon glycerin (see Glycerides, p. 277). Oxidizing agents con- 
vert it first into acrolein, acrylic aldehyde, C 3 H 4 0, and finally into acrylic 
acid. It does not combine readily with hydrogen, but in the presence of 
nascent hydrogen combination takes place slowly, with formation of pro- 
pylic alcohol. 



222 GENERAL MEDICAL CHEMISTRY. 

OH) 
Allyl oxide — Allylic ether — q 3 jt 5 [• O — exists in small quantities in 

3 5 J 

crude essence of garlic. It is obtained as a colorless liquid, having an 
alliaceous odor; insoluble in water; boiling at 82°, by a number of reac- 
tions, but best by the action of allyl iodide upon sodium allyl oxide: 



« 



Allyl iodide. Sodium allyl Sodium iodide. Allyl oxide, 

oxide. 

Allyl sulphide — Essence of garlic — p 3 xr 5 !■ S — is obtained by the ac- 
tion of an alcoholic solution of potassium sulphide upon allyl iodide; also 
as a constituent of the volatile oil of garlic, by macerating garlic, or 
other related vegetables, in water and distilling. Crude essence of garlic 
is thus obtained as a heavy, fetid, brown oil; this is purified by redis- 
tillation below 140°; contact with potassium and subsequent redistillation 
form calcium chloride. 

As thus obtained it is a colorless, transparent oil; lighter than water, 
sparingly soluble in water, very soluble in alcohol and ether; boils at 140°; 
has an intense odor of garlic. 

This substance does not exist naturally in the plant, or at least 
not in quantities at all approximating to those in which it is obtained from 
it; it is formed during the process of extraction by the action of water, 
probably in a manner similar to that in which essence of mustard is formed 
under similar circumstances. It is to the formation of allyl sulphide, 
which is highly volatile, that garlic owes the odor which it emits, espe- 
cially when heated with water, as in cooking. 

Allyl sulphoeyanate — Essential oil of mustard— p tt !■ S. — If the 

seeds of white or black mustard be strongly expressed, a bland, neutral oil 
is obtained, which resembles rapeseed and colza oils in its physical prop- 
erties, and in being composed of the glycerides of stearic, oleic and erucic 
acids. The cake remaining after the expression of this oil from black 
mustard, or the black-mustard seeds themselves, pulverized and mois- 
tened with water, gives off a strong, pungent odor. If the water be now 
distilled, a volatile oil passes over with it, which is the crude essential 
oil of mustard. 

In practice the powdered cake of black-mustard seeds, from which the 
fixed oil has been expressed, is digested with four to six parts of water for 
twenty-four hours, after which the water is distilled as long as any oily 
matter passes over; the oil is collected, dried by contact with calcium 
chloride, and redistilled. Essence of mustard may also be obtained syn- 
thetically by the action of allyl bromide or iodide upon potassium sulpho- 
eyanate, or by the action of allyl iodide upon silver sulphoeyanate. 

This essence does not exist preformed in the mustard, but results from 
the decomposition of a peculiar constituent of the seeds, potassium myro- 
nate, determined by a fermentation set up by another constituent, myro- 
sine 9 in the presence of water — the decomposition probably occurring 
according to the equation — 

C„H 18 NS,O 10 K = CNS s C a H t + C,H ls O + SO.HK 

Potassium myronate. Allyl sulphoeyanate. Glucose. Hydropotassic 

sulphate. 



ACIDS AND ALDEHYDES OF THE ACRYLIC SERIES. 



223 



Potassium myronate exists only in appreciable quantity in the black 
variety of mustard, from which it may be obtained in the shape of short, 
prismatic crystals, transparent, odorless, bitter; very soluble in water, 
sparingly so in alcohol. 

Myrosine is a nitrogenized ferment existing in the white as well as 
in the black mustard, and in other seeds. It may be obtained from white- 
mustard seeds, in an impure form, by extraction with cold water, filtering 
and evaporating the solution at a temperature below 40°; the syrupy 
fluid so obtained is precipitated with alcohol, the precipitate washed 
with alcohol, redissolved in water, and the solution evaporated below -40° 
to dryness. 

At temperatures above 40° myrosine becomes coagulated and inca- 
pable of decomposing potassium myronate, a change which is also pro- 
duced by contact with acetic acid. As the rubefacient and vesicant 
actions of mustard, when moistened with water, are due to the production 
of allyl sulphocyanate, it is obvious that neither vinegar, acetic acid, 
or heat greater than 40°, should be used in the preparation of mustard 
cataplasms. The prepared mustard plasters or papers which are now in 
use are made by spreading the flour of mustard, mixed with benzol or 
carbon disulphide and caoutchouc, upon paper. 

Pure allyl sulphocyanate is a transparent, colorless oil; sp. gr. 1.015 
at 20°; boils at 143°; has a penetrating, pungent odor, sparingly soluble 
in water, very soluble in alcohol and ether. When exposed to the light it 
gradually turns brownish yellow and deposits a resinoid material. When 
applied to the skin it produces rubefaction, quickly followed by vesication. 

Menthyl hydrate — Menthol — Menthic alcohol — Peppermint cam- 

O W ) 

phor — 10 4f [• O — is a superior homologue of allyl alcohol, and is a solid 

deposited by the essential oil of peppermint. When purified it forms color- 
less, prismatic crystals; insoluble in water, soluble in alcohol, ether, and 
in acids; fuses at 34° — 36°; boils at 213°; has the odor and taste of pep- 
permint strongly developed. It is capable of yielding, under suitable 
conditions, ethers of a radical, menthyl, and a hydrocarbon — menthene, 



ACIDS AND ALDEHYDES OF THE ACRYLIC SERIES. 

# 
These substances bear the same relation to the alcohols of the allyl 
series that the volatile fatty acids and the corresponding aldehydes bear 
to the ethylic series of alcohols. The following terms of the series have 
been obtained: 



Acids. 
C n H„_ 2 2 . 

Acrylic acid C 3 H 4 

Orotonic C 1 2 "H 6 

Angelic C 5 2 H 8 

Pyroterebic C 6 O 2 H 10 

Oleic C 18 2 H 3 , 



Aldehydes. 
CJEE 2n _ 2 0. 

Acrolein C 3 OH 4 

Crotonic aldehyde ^ 4 OH 6 



The acids of this series differ from those containing the same number 
of carbon atoms in the formic series, by containing two atoms of hydro- 



224 GENERAL MEDICAL CHEMISTRY. 

gen less; they are readily converted into acids of the formic series by 
the action of potassium in fusion, which forms with them the potassium 
salt of acetic acid and that of the acid of the formic series containing 
the complementary number of carbon atoms, thus: 

C 3 H 4 2 + 2KHO = C 2 H 3 2 K + CH0 2 K + H a 

Acrylic acid. Acetate. Forniiate. 

O TT O ) 
Acrylic acid — 3 Vr > O — is obtained by oxidation of acrolein, 

acrylic aldehyde, by silver oxide, and is formed in a number of other re- 
actions; as a product of the oxidation of acrolein, it is formed when grease 
is strongly heated. 

It is a colorless, highly acid liquid; has a penetrating odor; solidifies 
at 7°; boils at 140°; distils unchanged with vapor of water. 

Nascent hydrogen unites with it to form proprionic acid. It readily 
forms crystallized salts and ethers. There exist products of substitution 
with chlorine and bromine. 

Acrylic aldehyde — Allylic aldehyde — Acrolein — C 3 H 3 ) _ w , 

the fats and fixed oils are decomposed by heat, a disagreeable, irritating 
odor is produced, which is due to the formation of acrolein by the dehy- 
dration of the glycerin contained in the fatty material. Acrolein may 
be obtained by heating glycerin with strong sulphuric acid, or with hy- 
dropotassic sulphate. Glycerin is the alcohol (hydrate) of a radical hav- 
ing the same composition as allyl, but so differing from it in constitution 
as to be trivalent in place of univalent. 

(C,H.)'"(OH), = 2H,0 + (C,H,0)'H 

Glycerin. Water. Acrolein. 

The condensed product of this reaction, which must be conducted in 
an atmosphere of carbon dioxide, in a capacious retort and receiver, and 
in such a way that the uncondensed products are discharged into the 
open air, are purified by contact with lead oxide, and subsequent distilla- 
tion from calcium chloride. 

Acrolein is a colorless, limpid liquid; lighter thai! water; boils at 52.4°; 
sparingly soluble in water; more soluble in alcohol ; very volatile, its 
vapor having a very pungent odor and producing irritation and suffoca- 
tion to such a degree that the presence of a very small quantity in a con- 
fined space renders the atmosphere irrespirable ; its taste is caustic. 
When freshly prepared it is neutral in reaction, but on contact with air it 
rapidly becomes acid by oxidation. For the same reason it does not keep 
well, even in closed vessels; on standing it deposits a nocculent material, 
which has been called disocryl, while at the same time formic, acetic, and 
acrylic acids are formed. 

Oxidizing agents convert acrolein into acrylic acid, or, if they be ener- 
getic, into a mixture of formic and acetic acids. The caustic alkalies 
produce from it resinoid substances similar to those formed from acetic 
aldehyde. With ammonia it forms a crystalline, odorless compound, 
which behaves as a base. 

Acrolein is formed whenever glycerin, or any substance containing it 
or its compounds with the fatty acids, is heated to a temperature sufficient 



ACIDS AND ALDEHYDES OF THE ACRYLIC SERIES. 225 

to effect its decomposition; for this reason, and because of the irritating 
action of the acrolein, the heavy petroleum-oils are preferable to those of 
vegetable or animal origin for the lubricating of machinery operated in en- 
closed places. 

n n A j 

Crotonic acid, 4 \t [ — was first obtained from croton-oil, oleum 

tiff Hi (U. S.), in which it exists in combination with glycerin, and accom- 
panied by the glycerin ethers of several other fatty acids; it is, however, 
neither the vesicant nor the purgative principle of the oil. It may be 
obtained by saponification of croton-oil, or, better, by the action of potas- 
sium hydrate upon allyl cyanide: 

C 3 H 5 ,CN + KHO + H 2 = C 4 H 5 0,OK + NH 3 

Allyl cyanide. Potassium Water. Potassium Ammonia, 

hydrate. crotonate. 

It is an oily liquid; solidifies at — 5°; acrid in taste; gives off highly 
irritating vapors at temperatures slightly above 0°. When taken inter- 
nally it acts as an irritant poison. 

An acid obtained by oxidation of crotonic aldehyde is probably an iso- 
mere, as it is in the form of crystals at ordinary temperatures, and only 
fuses at 73°. 

Crotonic acid forms well-defined salts, and products of substitution 
with chlorine and bromine. 

Crotonic aldehyde, 4 6 tt[. — If aldehyde, water, and hydrochloric 

acid be mixed together at a low temperature, and the mixture exposed to 
diffused daylight for some days, an oily liquid is formed, which, after puri- 
fication, has the composition C 4 H 8 2 . This substance, known as aldol, 
when exposed to heat, is decomposed into water and crotonic aldehyde: 

0.H.O, = H,0 + C 4 H,0 

Aldol. Water. Crotonic aldehyde. 

Crotonic aldehyde is a colorless liquid; boils at 105°; gives off highly 
irritating vapors. It is only of interest as bearing the same relation to 
croton chloral that aldehyde does to chloral. 

TT CI O ) 
Croton chloral — Trichlorocroton aldehyde — 4 2 Vr !• — a sub- 
stance which has been recently introduced into medicine as an anaesthetic 
whose action is particularly directed to the sensory nerves distributed to 
the head and face. It is prepared by directing a current of chlorine 
through acetic aldehyde as ordinary chloral is obtained by the action of 
chlorine upon ethylic alcohol (see p. 201). The first action of the chlorine 
is to convert ethylic aldehyde into crotonic aldehyde by condensation and 
elimination of water; in the second stage of the reaction the substitution 
of three atoms of chlorine for an equal number of atoms of hydrogen in 
the croton aldehyde thus formed takes place. 

C IT O ) 
Angelic acid, b v j- O — exists in angelica root, Angelica (U. S.), 

in the flowers of chamomile, Anthemis (U. S.), and in croton-oil. 

It crystallizes in colorless prisms, which fuse at 45.5°; boils at 185°; 

15 



226 GENERAL MEDICAL CHEMISTRY. 

has an aromatic odor and an acid, pungent taste; sparingly soluble in cold 
water; readily soluble in hot water, alcohol, and ether. By the action of heat 

it is converted into its isomere, methylcrotonic acid, 4 4 ^ 3 Vr [ O. 

The Essence of chamomile, Oleum anthimidis (Br.), is a mixture in vary- 
ing proportions of compound ethers, in which amyl and butyl angelates 
predominate. 

Oleic acid, 15 3 Vr [ O — exists as its glycerin ether, olein, in most, 

if not in all, the fats and in all fixed oils. It is obtained in an impure 
form on a large scale, industrially, as a by-product in the manufacture of 
candles. This product is, however, very impure; to purify it, it is first cooled 
to zero, the liquid portion collected, cooled to — 10°, expressed, and the 
solid portion collected; this is melted and treated with half its weight of 
massicot; the lead oleate so obtained is dissolved out by ether; the de- 
canted ethereal solution is shaken with hydrochloric acid, the ethereal 
layer decanted and evaporated, when it leaves oleic acid, contaminated 
with a small quantity of oxyoleic acid, from which it can be purified only 
by a tedious process. 

Pure oleic acid is a white, pearly, crystalline solid, which fuses to a 
colorless liquid at 14°; when cold liquid oleic acid is warmed, it solidifies 
at 4°; it is odorless and tasteless; soluble in alcohol, ether, and cold sul- 
phuric acid; insoluble in water; sp. gr. 0.808 at 19°; neutral in reaction. 
It can be distilled in vacuo without decomposition, but when heated in 
contact with air it is decomposed with formation of hydrocarbons, vola- 
tile fatty acids, and sebacic acid. It dissolves the fatty acids readily, 
forming mixtures whose consistency varies with the proportions of 
liquid and solid acid which they contain. The solid acid is but little 
altered by exposure to air, but when liquid it absorbs oxygen rapidly, 
becomes yellow, rancid, acid in reaction, and incapable of solidifying 
when cooled; these changes take place the more rapidly the higher the 
temperature. 

Chlorine and bromine attack oleic acid with formation of products of 
substitution. If oleic acid be heated with an excess of caustic potassa to 
200°, it is decomposed into palmitic and acetic acids: 

C 18 H„0 3 + 2KHO = C 16 H a ,O a K + s H 3 O 2 K + H„ 

Oleic acid. Potassium Potassium Potassium 

hydrate. palmitate. acetate. 

A reaction which is utilized industrially to obtain hard soaps, palmitates, 
form olein, which itself only forms soft soaps. Cold sulphuric acid dis- 
solves oleic acid, and deposits it unaltered on the addition of water; but 
if the acid solution be heated it turns brown and gives off sulphur dioxide. 
Nitric acid oxidizes it energetically with formation of a number of vola- 
tile fatty acids and acids of another series — suberic, adipic, etc. The 
oleates of the alkaline metals are soft, soluble soaps; those of the earthy 
metals are insoluble in water, but soluble in alcohol and in ether. 

Elaidic acid is an isomere of oleic acid, produced by the action upon 
it of nitrous acid in the preparation of TJnguentum hydrargyri,nitratis (U. 
S., Br.). The nitrous fumes formed convert the oleic acid contained in 
the oil and lard used into elaidic acid, which exists in the ointment in 
combination with mercury. 



SECOND SERIES OF HYDROCARBON'S OLEFIKES. 227 



POLYATOMIC COMPOUNDS. 

The organic compounds hitherto considered may be looked upon as 
compounds of univalent carbon radicals, these radicals existing in the 
alcohols and acids in combination with an atom each of oxygen and 
hydrogen; they are called monoatornic because they contain a single 
atom of hydrogen capable of being replaced by an alcoholic radical. 
There exist other carbon compounds, in which the radicals, containing a 
less number of hydrogen atoms as compared with the number of carbon 
atoms, have a valence greater than one; these radicals form acids, alcohols, 
etc., in which the number of atoms of replaceable hydrogen is greater 
than one, and which are designated as polyatomic. 



NON-SATURATED HYDROCARBONS. 

Besides the compounds of carbon and hydrogen described on pp. 149— 
157, in which all the valences of the carbon atoms are satisfied either by 
the attachment of hydrogen atoms, or by the interchange of a single 
valence between neighboring carbon atoms, there exist many others in 
which the proportion of hydrogen to carbon is less. These compounds 
are non-saturated in this, that they are capable of uniting directly with 
atoms of other elements, or with radicals, to form products of addition, 
while the composition of the saturated hydrocarbons can only be modified 
by substitution y they are not, however, to be considered as containing 
any unsatisfied valence. 

These hydrocarbons are very numerous, and may be arranged in ho- 
mologous series, as shown in the following table (p. 228), each succeeding 
series containing a less amount of hydrogen in proportion to the carbon: 

Each series and its derivatives will be considered in the order given 
in the table. 



SECOND SERIES OF HYDROCARBONS— OLEFINES. 

Series C n H 2n . 

The terms of this series contain two atoms of hydrogen less than the 
corresponding terms of the first series; they differ in constitution in this, 
that, while in the first series a single valence is exchanged between each 
two neighboring carbon atoms, in the second series two valences are 
exchanged between two of the carbon atoms: 

CeeH 3 C = H, 

C = H 9 C-H 

I II 

CeeH 3 = H, 

Propane. Propylene. 

They are designated as olefines, a name derived from a property of the 
second in the series, which was formerly known as olefiant gas; or, to dis- 



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SECOND SERIES OE HYDROCARBONS OLEEINES. 229 

tinguish them from the terms of the first series, by the terminations ylene or 
ene, thus, the second is called ethylene or ethene. They behave as divalent 
radicals. 

Methene — Methylene — CH 2 — is of doubtful existence, known only 
in combination. Ethene — Ethylene — Olefiant gas — Elayl — Heavy car- 

CH 2 
buretted hydrogen — || — is formed by the dry distillation of fats, resins, 

OH 3 
wood, /and coal, and is one of the most important constituents of illumina- 
ting gas. It is also obtained by the dehydration of alcohol or ether. 

It has been obtained synthetically in three ways: 1st, by passing a mix- 
ture of hydrogen sulphide and carbon monoxide over iron or copper heated 
to redness; 2d, by heating acetylene in the presence of hydrogen, or by 
the action of nascent hydrogen upon copper acetylide; 3d, by the action 
of hydrogen upon the chloride C 2 C1 4 , obtained by the action of chlorine 
upon carbon disulphide. 

It is prepared in the laboratory by the dehydration of alcohol by sul- 
phuric acid: a mixture of four parts by weight of sulphuric acid and one 
part of alcohol is placed in a flask containing enough sand to form a thin 
paste, and gradually heated to about 170°; the gas, which is given off in 
abundance, is purified by causing it to pass through wash-bottles con- 
taining water, an alkaline solution, and concentrated sulphuric acid, and 
may be collected over water. 

Pure ethylene is a colorless gas; tasteless; has a faint odor resembling 
that of salt water, or an ethereal odor when impure; irrespirable; spar- 
ingly soluble in water, more soluble in alcohol. It burns with a luminous, 
white flame, and forms explosive mixtures with air and oxygen. When 
heated for some time at a dull red heat it is converted into acetylene, 
ethyl and methyl hydrides, a tarry product, and carbon. 

Ethylene readily enters into combination. It unites with hydrogen 
to form ethyl hydride, C 2 H 6 . With oxygen it unites explosively on the 
approach of a flame, with formation of carbon dioxide and water. Oxidiz- 
ing agents, such as potassium permanganate in alkaline solution, convert 
it into oxalic acid and water. A mixture of chlorine and etheno, in the 
proportion of two volumes of the former to one of the latter, unite with 
an explosion on contact with flame, the union being attended with a 
copious deposition of carbon and the formation of hydrochloric acid. 
Chlorine and ethene, mixed in equal volumes and exposed to diffused day- 
light, unite slowly, with formation of an oily liquid; ethene chloride, C 2 
H 4 C1 2 ; Dutch liquid, to whose formation ethene owes the name olefi- 
ant gas. By suitable means ethene may also be made to yield chlorinated 
products of substitution, the highest of which is carbon tetrachloride, C, 
01 4 . Bromine and iodine also form products of addition and of substitu- 
tion with ethene. By union with (OH) 2 it forms glycol (q. v.). It slowly 
dissolves in ordinary sulphuric acid, with formation of sulphovinic acid; 
with fuming sulphuric acid it combines with elevation of temperature and 
formation of ethionic anhydride. 

When inhaled, diluted with air, ethene produces effects somewhat 
similar to those of nitrous oxide. 

The higher terms of this series are of theoretical interest only, except 
the fifth. 

Pentene — Amylene or valerine — C B H 10 — a colorless, mobile liquid, 
boiling at 39°; obtained by heating amylic alcohol with a concentrated 
solution of zinc chloride. Its use as an anaesthetic has been suggested. 



230 GENERAL MEDICAL CHEMISTKY. 

CH.C1 



-a 



Ethene chloride — Bichloride of ethylene — Dutch liquid — 

CH 2 C1 
is obtained by passing a current of ethene through a retort in which 
chlorine is being generated and connected with a cooled receiver. The 
distillate is washed with a solution of caustic potassa, afterward with 
water, and is finally rectified. 

It is a colorless, oily liquid, which boils at 82.5°; has a sweetish taste 
and an ethereal odor. It is isomeric, but not identical with the chloride of 

monochlorinated ethyl, I , which boils at 64°. It is capable of fixing 

other atoms of chlorine by substitution for hydrogen, and thus forming a 
series of chlorinated derivatives, the highest of which is O a Cl 6 . 



DIATOMIC ALCOHOLS. 

Series C n H an+a O a . 

These substances, which are of great theoretical interest, were discov- 
ered in 1856 by Wurtz, and are usually designated as glycols. They are 
the hydrates of the hydrocarbons of the series C„H 2M , and consist of those 
hydrocarbons, playing the part of divalent radicals, united with two groups 



ave seen 



OH; their general typical formula is then (CJBl^)'' ) ^ -vy- i 

(p. 150) that the primary monoatomic alcohols contain the group of 
atoms (CH 2 OH)' united with n(C n H 2n +i); the primary glycols are simi- 
larly constructed, and consist of twice the group (CH 2 OH), united in the 
higher terms to n(0 w H 2W ). The constitution of the glycols and their re- 
lations to the monoatomic alcohols is indicated by the following formulas: 

CH a OH CH a OH 

0H a CH a 

CH 3 0H 2 OH 

Primary propyl acohol. Primary propyl glycol. 

As the monoatomic alcohols are such by containing in their molecules 
a group (OH), closely attached to an electro-positive group, and capable 
of removal and replacement by an electro-negative group or atom, so the 
glycols are diatomic by the fact that they contain two such groups (OH) ; 
as the monoatomic alcohols are therefor only capable of forming a single 
ether with a monobasic acid, the glycols are capable of forming two such 
ethers: 



OH. (C,H,0.)' 

CH 3 


CH, (C,HA)' 
CH,OH 


CH, (C.H.O,)' 
OH, (CJIA)' 


Ethyl acetate. 


Monoacetic glycol. 


Diacetic glycol. 



DIATOMIC ALCOHOLS. 231 

For the products of oxidation of the glycols, see p. 232 et seq. 

0H a OH 
Ethene glycol — Ethylene glycol or Alcohol or Hydrate — | . — 

CH 2 OH 
This, the best known of the glycols, was first obtained by Wurtz. It 
is prepared by the action of dry silver acetate upon ethylene bromide: 

OABt. + 2C 2 H s O a Ag = 2AgBr + (C.H.OJ.C.H, 

Ethylene bromide. Silver acetate. Silver bromide. Diacctic glycol. 

The ether so obtained is purified by redistillation, and decomposed by 
heating for some time with barium hydrate: 

(OMW + Ba °A = (C,H,0,),Ba + 0^,0^ 

Diacetic glycoL Barium hydrate. Barium acetate. Glycol. 

It is a colorless, slightly viscous liquid; odorless; faintly sweet; sp. 
gr. 1.125 at 0°; boils at 197°; sparingly soluble in ether; very soluble in 
water and in alcohol. 

It is not oxidized by simple exposure to air, but on contact with pla- 
tinum black it is oxidized to glycolic acid; more energetic oxidants 
transform it into oxalic acid. Chlorine acts slowly upon glycol in the 
cold; more rapidly under the influence of heat, producing chlorinated 
and other derivatives. By the action of dry hydrochloric acid upon 
cooled glycol, a product is formed intermediate between it and ethylene 
chloride, a neutral compound — ethene chlorhydrate or ethene chlorhydrin, 
CH 2 OH 

, which boils at 130°. 
CH 2 C1 

Ethene oxide — Ethylene oxide — (C 2 H 4 )"0. — This substance, isomeric 
with aldehyde, is obtained by the action of potassium hydrate upon ethene 
chlorhydrate, mentioned above. 

It is a transparent, volatile liquid; boils at 13.5°; gives off inflamma- 
ble vapors; mixes with water in all proportions. It is capable of uniting 
directly with water to form glycol; and with hydrochloric acid gas to 
regenerate ethene chlorhydrate. 

The superior homologues of ethene glycol and of ethene oxide are only 
of interest from a theoretical point of view. 

Taurine, S0 3 C 2 H 7 N — is isomeric with a derivative of glycol, isethi- 
onamide. It is obtained from ox-bile by boiling with dilute hydrochlo- 
ric acid; decanting and concentrating the liquid; separating from the 
sodium chloride which crystallizes; evaporating further, and precipitating 
with alcohol. The deposit is purified by recrystallization from alcohol. 

It crystallizes in large, transparent, oblique, rhombic prisms, permanent 
in air, quite soluble in water, almost insoluble in absolute alcohol and 
ether. 

Taurine has acid properties and forms salts; it is not attacked by sul- 
phuric, nitric or nitromuriatic acid, but is oxidized by nitrous acid, with 
formation of water, nitrogen, and isethionic acid. 

It exists in the animal economy, in the bile in taurocholic acid (q. v.) ; 
and has also been detected in the intestine and fasces, muscle, blood, liver, 
kidneys, and lungs; the pneumic acid, described as existing in the lung, 
is taurine. When taken internally, it is eliminated by the urine, not in its 
own form, but as taurocarbamic or isethionuric acid, C 3 II 8 N a S0 8 . 



232 GENEKAL MEDICAL CHEMISTKY. 



ACIDS DERIVED FROM THE GLYCOLS. 

As the acids of the acetic series are obtained from the primary mono- 
atomic alcohols by the substitution of O for H in the characterizing 
group CH a OH: 

CH 3 CH 3 

I I 

CH 2 ,OH CO,OH 

Ethyl alcohol. Acetic acid. 

so the diatomic alcohols may, by oxidation, be made to yield acids, formed 
by the same substitution of O for H 2 . But the glycols differ from the 
monoatomic alcohols in containing two groups CH 2 OH, and they conse- 
quently yield two acids, as the substitution occurs in one or both of the 
alcoholic groups: 



CH 2 ,OH 

1 


CH 2 ,OH 


CO,OH 

1 


OH 2 ,OH 


CO,OH 


CO,OH 


Ethene glycol. 


Glycolic acid. 


Oxalic acid 



A study of these two acids shows them to be possessed of peculiar 
differences of function. Each of them contains two groups (OH), whose 
hydrogen is capable of replacement by an acid or alcoholic radical: 



CH 2 ,OC 2 H 6 


CH„,OH 


CH,OC,H, 


CO,OH 

1 


CO,OC„H, 

00,00,11, 


COOH 


CO,O0 s H t 


00,00,11, 


CO,0'C 2 H 6 


Ethylglycolic acid. 


Ethyl glycolate. 


Ethyl ethylglycolate. 


Ethyloxalic acid. 


Ethyl oxalate. 



They are, therefor, both said to be diatomic. The ability, however, of 
the two acids to form salts is not the same, for while oxalic acid is capable 
of forming two salts of univalent metals, and a salt of a divalent metal 
with a single molecule of the acid; glycolic acid only forms a single salt of an 
univalent metal, and two of its molecules are required to form a salt of a 
divalent metal; in other words, glycolic acid is monobasic while oxalic acid 
is dibasic. It is only that atom of hydrogen which is contained in the elec- 
tro-negative group COOH, which is replaceable as acid hydrogen, while 
that of the electro-positive group CH 2 OH is only replaceable, as is the 
corresponding hydrogen of an alcohol. 

In general terms, therefor, the atomicity of an organic acid may be 
greater than its basicity, the former representing the number of hydrogen 
atoms contained in its molecule, which are capable of being displaced by 
alcoholic radicals, while the latter represents the number of hydrogen 
atoms replaceable by electro-positive elements or radicals, with formation 
of salts or of ethers. 

There may, therefor, be obtained from the glycols, by more or less com- 
plete oxidation, two series of acids; those of the first are diatomic and 
monobasic; those of the second diatomic and dibasic. 



DIATOMIC AND MONOBASIC ACIDS. 233 

DIATOMIC AND MONOBASIC ACIDS. 

Series C n H 2n 3 . 
The acids of this series at present known are: 



(Carbonic acid) C0 3 Hi 

Glycolic acid C;>0 3 H4 

Ethyleno-lactic acid .. C 3 3 II 6 



Butylactic acid. .C,0 3 H 8 
Oxy valeric acid.C 3 O 3 H 10 



Leucic acid C 6 3 H ia 

(?)GEnantkic acid.Ci 4 02H 28 



The first-named of these acids, although not capable, so far as yet 
known, of existing in the free state, is widely represented in nature in 
the shape of its salts, the carbonates. Its position in this series is an 
anomaly, and at first sight a contradiction, as it is certainly not a mono- 
basic, but a distinctly dibasic acid, or, more properly speaking, would be 
such were it obtained in a state of purity; it is, however, in this position 
as the inferior homologue of glycolic acid that carbonic acid is most 
naturally placed, and the dibasic nature of the latter acid does not pre- 
sent any valid objection to such a position, for if we consider one term of 
a series as derivable from its superior homologue by the subtraction of 
CH 2 , and if we bear in mind that the basic nature of the hydrogen atom 
in a group OH depends upon its close union with the group CO (or with 
some other electro-negative group), it will become evident that the inferior 
homologue of glycolic acid must contain two groups OH united to one 
CO, and must, therefor, be dibasic: 

CH 3 OH OH /mT 

| - CH 2 = | or CO/XS 

CO,OH CO,OH ^ Uil 

Glycolic acid. Carbonic acid. 

The other acids of the series are formed: First. — By the partial oxida- 
tion of the corresponding glycol: 

CH„OH CH a OH .pv 

+ 0, = I + g >0 



c 



)H 2 0H C0,0H H / 

Glycol. Glycolic acid. Water. 

Second. — By the combined action of water and silver oxide upon the 
monochlor-acid of the acetic series, or by heating the alkaline salt of 
such an acid with water or potassium hydrate: 



CH 3 C1 
COOK 


H\ . 
H/ u " 


CH 2 OH 
CO,0H 


+ KC1 


Potassium 


Water. 


Glycolic acid. 


Potassium 


monochloracetate. 






chloride. 



Third. — By reducing the corresponding acid of the oxalic series by 
^nascent hydrogen: 



COOH CH 2 OH ^ 

+ 2H a = | + S >0 
JOOH COOH **/ 

Oxalic acid. Glycolic acid. Water. 



I 



234 GENERAL MEDICAL CHEMISTRY. 

Carbonic Acid, Co/qjj 

Although this acid has not been isolated, it is probable that it exists 
in aqueous solutions of carbon dioxide, which have an acid reaction, while 
the dry oxide is neutral to test-paper. Its salts, the carbonates, are 

widely distributed in nature, and have the general composition CO/ qtt 

«<8S, « co <3> 



Oxides of Carbon. 

These are two in number: 

Carbon monoxide CO 

Carbon dioxide C0 3 

Carbon Monoxide. 

Carbonic oxide — Carbonous oxide — CO — was discovered in 1799, by 
Priestley. It does not exist in nature, but is formed whenever carbon is 
burned with a supply of air insufficient to the formation of carbon dioxide; 
when carbon dioxide is partially reduced by passage over red-hot char- 
coal, iron, zinc, etc., and when vapor of water is decomposed by coal 
heated to bright redness. 

When required in the laboratory, it is obtained either: 1st, by passing 
dry carbon dioxide over red-hot charcoal; or, 2d, by heating together 
oxalic and sulphuric acids: 



0.0 4 H. 


+ 


S0 4 H, , 


= S0 4 H 2 


+ 


H,0 


4- CO + 


oo, 


Oxalic acid. 




Sulphuric 
acid. 


Sulphuric 
acid. 




Water. 


Carbon 
monoxide. 


Carbon 
dioxide. 



The resulting gas is passed through wash-bottles containing lime-water, 
which retains the dioxide. 

It is a colorless, odorless, tasteless gas; has been recently liquefied by 
Cailletet; sp. gr. 0.9678 — A, 14 H; very sparingly soluble in water and 
in alcohol, its solubility in the latter fluid being remarkable for not vary- 
ing between 0° and 20°. 

It burns in air with formation of carbon dioxide and with a blue 
flame; its mixtures with air and oxygen are explosive on contact with 
flame if the proportion be not too far removed from CO:0; it is also 
oxidized toCO a in the cold by chromic acid. The most valuable property 
of carbon monoxide is its power of reducing many metallic oxides at a red 
heat, a property which is largely utilized in metallurgy. It is rapidly ab- 
sorbed by ammoniacal solutions of the cuprous salts, a property utilized in 
gas-analysis; it is also absorbed by hot potassium hydrate solution, with 
formation of potassium formiate. Being a non-saturated compound, it 
readily unites directly with other elements, as with oxygen, to form CO a 



CAEBOX MONOXIDE. 235 

and with chlorine to form COCl 2 , the latter a colorless, suffocating" gas, 
known as phosgene, or carbonyl chloride. 

Toxicology. — Carbon monoxide is an exceedingly poisonous gas, and 
is the chief toxic constituent of the gases given off from blast-furnaces, 
from defective flues, and open coal or charcoal fires, and of illuminating 
gas. An atmosphere containing but a small proportion of this gas pro- 
duces asphyxia and death, even if the quantity of oxygen present be equal 
to or even greater than that normally existing in the atmosphere; 0.5 
per cent, of carbon monoxide in air is sufficient to kill a small bird in a 
few moments, and one per cent, proves fatal to small mammals. 

Poisoning by carbon monoxide may occur in several ways. By inha- 
lation of the gases discharged from blast-furnaces and from copper-fur- 
naces, the former containing twenty-five to thirty-two per cent., and the 
latter thirteen to nineteen per cent, of carbon monoxide. By the fumes 
given off from charcoal burned in a confined space — a favorite means of 
suicide, especially in France — the gas produced by this combustion is chiefly 
a mixture of the two oxides of carbon, the dioxide predominating largely, 
especially when the combustion is most active. The following is given 
by Leblanc as the composition of an atmosphere produced by burning 
charcoal in a confined space, and which proved rapidly fatal to a dog: 
oxygen, 19.19; nitrogen, 76.62; carbon dioxide, 4.61; carbon monoxide, 
0.51; marsh-gas, 0.04. Obviously the deleterious effects of charcoal-fumes 
are more rapidly fatal in proportion as the combustion is imperfect and 
the room small and ill-ventilated. 

A fruitful source of carbon monoxide poisoning, sometimes fatal, but 
more frequently producing languor, headache, and debility, is to be found 
in the stoves, furnaces, etc., used in heating our dwellings and other 
buildings, especially when the fuel is anthracite coal. This fuel produces 
in its combustion, when the air-supply is not abundant, considerable quan- 
tities of carbon monoxide, to which a further addition may be made by a 
reduction of the dioxide, also formed, in passing over red-hot iron; this 
poisonous gas may find its way into the rooms either through cracks or 
other defects in the stoves, flues, or pipes; by occasional downward cur- 
rents of air passing over fires in open fireplaces, or, much more frequently, 
by direct passage through the heated metal. Experiment has shown that 
metals, notably cast-iron, are quite pervious to gases when heated to red- 
ness; when, therefor, a stove or the fire-box of a hot-air furnace becomes 
red-hot, a portion of the gases formed, by the combustion of the fuel 
passes through the pores of the metal to contaminate the air without, and 
give rise to carbonic oxide poisoning to a degree depending upon the de- 
gree of imperfection of the ventilation, the nature of the fuel, and the 
amount of air supplied to it. The obvious precautions required to avoid 
this form of what may be called chronic carbonic oxide poisoning, and 
which is by no means uncommon, are: 1st, to have the stoves or furnaces 
lined with fire-clay, which tends to prevent their overheating and to di- 
minish their perviousness to gases; 2d, to avoid heating to redness; 3d, 
to furnish an abundant supply of air to the fuel; 4th, to secure proper 
ventilation; and 5th, in the case of hot-air furnaces, to obtain, by an 
abundant supply of external air to the air-chamber, a large supply of mod- 
erately heated air rather than a small quantity of very hot air. 

Of late years cases of fatal poisoning by coal-gas are of very frequent 
occurrence, caused either by accidental inhalation, by inexperienced per- 
sons blowing out the gas, or by suicides. There can be little doubt that 
the most actively poisonous ingredient of coal-gas is carbon monoxide, 



236 GENERAL MEDICAL CHEMISTRY. 

which exists in the ordinary illuminating gas in the proportion of 4 to 
7.5 per cent., and in water-gas, made by decomposing superheated steam 
by passage over red-hot coke, and subsequent charging with vapor of hy- 
drocarbons, in the large proportion of thirty to thirty-five per cent. 

The method in which carbon monoxide produces its fatal effects is by 
forming with the blood-coloring matter a compound which is more stable 
than oxyhemoglobin, and thus causing asphyxia by destroying the power 
of the blood-corpuscles of carrying oxygen from the air to the tissues. 
This compound of carbonic oxide and hemoglobin is quite stable, and 
hence the symptoms of this form of poisoning are very persistent, lasting 
until the place of the coloring-matter thus rendered useless is supplied by 
new-formation. The prognosis is very unfavorable when the amount of 
the gas inhaled has been at all considerable; the treatment usually fol- 
lowed, i. 6., artificial respiration, and inhalation of oxygen, failing to restore 
the altered coloring-matter. There would seem to be no form of poison- 
ing in which transfusion of blood is more directly indicated than in that 
by carbon monoxide. 

Detection after death. — The blood of those asphyxiated by carbon 
monoxide is persistently bright red in color; when suitably diluted and 
examined with the spectroscope, it presents two absorption-bands very 
similar to those of oxyhemoglobin (see p. 369), but more equal to each 
other in intensity and slightly nearer the violet end of the spectrum; 
owing, however, to the greater stability of the carbonic oxide compound, 
its spectrum may be readily distinguished from that of the oxygen com- 
pound by the addition of a reducing agent (an ammoniacal solution of 
ferrous tartrate), which changes the spectrum of oxyhemoglobin to the 
single-band spectrum of reduced haemoglobin, while that of the carbon 
monoxide compound remains unaltered, or only fades partially. 

If a solution of caustic soda of sp. gr. 1.3 be added to normal blood, 
a black, slimy mass is formed, which, when spread upon a white plate, 
has a greenish brown color; the same reagent added to blood altered by 
carbonic oxide forms a firmly clotted mass, which in thin layers upon a 
white surface is bright red in color. 

For the method of detecting and determining carbon monoxide in 
gaseous mixtures, see p. 244. 



Carbon Dioxide. 

Carbonic anhydride — Carbonic acid gas — C0 2 — exists in small pro- 
portion in the atmosphere, and in solution in natural waters. It is formed 
whenever a substance containing carbon is burned in air or oxygen, and 
when a carbonate is decomposed by a stronger acid. 

It is best obtained by decomposing a natural carbonate, marble or 
limestone, by a mineral acid — hydrochloric acid. 

At ordinary temperatures and pressures it is a colorless gas; produces 
a sense of suffocation when inhaled; has an acidulous taste; sp. gr. 1.529 
at 0°; soluble in an equal volume of water at the ordinary pressure. 
When subjected to a pressure of thirty-eight atmospheres at 0°, fifty 
atmospheres at 15°, or seventy-three atmospheres at 30°, it is converted 
into a transparent, mobile liquid, by whose evaporation, when the pres- 
sure is relieved, a degree of cold is produced sufficient to solidify a por- 
tion as a snow-like mass, which, by spontaneous evaporation in air, pro- 
duces a temperature of — 90°. 



CARBON DIOXIDE. 



237 



Carbon dioxide neither burns nor does it support combustion; when 
heated to 1,300°, it is decomposed into carbon monoxide and oxygen; a 
similar decomposition is brought about by the passage through it of 
electric sparks. When heated with hydrogen it yields carbon monoxide 
and water; when potassium, sodium, or magnesium is heated in an atmos- 
phere of carbon dioxide, the gas is decomposed with formation of a car- 
bonate and separation of carbon. When caused to pass through solutions 
of the hydrates of sodium, potassium, calcium, or barium, it is absorbed, 
with formation of the carbonates of those elements, which, in the case of 
the last two, are deposited as white precipitates. Solution of potash is 
frequently used in analysis to absorb carbon dioxide, and lime and baryta 
water as tests for its presence. The hydrates mentioned also absorb 
carbon dioxide from moist air. 

Atmospheric carbon dioxide. — Carbon dioxide is a constant consti- 
tuent of atmospheric air in small and varying quantities; the mean 
amount in free country air being about four parts in ten thousand. The 
variations in amount under different conditions is shown in the following 
table: 

Amount of Carbon Dioxide in Aie. 



Collected at 



Paris 

Andilly — twenty miles from Paris 

Paris — Day 

Night 

Ocean — Day 

Night 

Day 

Night 

Geneva 

Meadow — three-fourths mile from G-eneva 

Dry months , 

After long rains 

December, damp and cloudy 

January, frost . . . 

January, thaw 

Lake Geneva 

Arctic regions 

Gosport barracks 

Anglesey barracks 

Hilsey Hospital 

Portsmouth Hospital 

Cell in Pentonville Prison 

Cell in Chatham Prison 

Boys' school — 69 cubic feet per head 

Room — 51 cubic feet per head 

Girls' school — 150 cubic feet per head. . . . 

Greenhouse— Jardin des Plantes 

Theatre — Parquet 

Near ceiling 

Lead mine — Lamps burn 

Lamps extinguished 

Grotto del Cane 



Parts in 10,000. 


Determined by 


3.190 


Boussingault and Lewy. 


2.989 


Boussingault and Lewy. 


3.9 


Boussingault. 


4.2 


Boussingault. 


5.42 


Lewy. 


3.346 


Lewy. 


3.011 


Thorpe. 


2.995 


Thorpe. 


4.68 


Saussure. 


4.79 to 5. 18 


Saussure. 


3. 57 to 4. 56 


Saussure. 


3.85 to 4.25 


Saussure. 


4.57 


Saussure. 


4.27 


Saussure. 


4.39 


Saussure. 


4.83 to 6.41 


Moss. 


6.45 


Chaumont. 


14.04 


Chaumont. 


4.72 


Chaumont. 


9.76 


Chaumont. 


9.89 


Chaumont. 


16.91 


Chaumont. 


31 


Roscoe. 


52.8 


Weaver. 


72.3 


Pettenkofer 


1.0 




23.0 




43.0 




80.0 


F. Leblanc. 


390.0 


F. Leblanc. 


7,360.0 


F. Leblano. 



It will be observed that on land the amount is greater by night than 
by day, while the reverse is the case at sea; on land the green parts of 



233 



GENERAL MEDICAL CHEMISTRY. 



plants absorb carbon dioxide during the hours of sunlight, but not during 
those of darkness. The increase in the amount in air over large bodies 
of water during the day-time is due to the less solubility of carbon di- 
oxide in the surface-water when heated by the sun's rays. The absence 
of vegetation accounts for the large quantity of carbon dioxide in the air 
of the polar regions, and the same cause, aided by an increased produc- 
tion, for its excess in the air of cities over that of the country. 

The sources of atmospheric carbon dioxide are: 

First. — Tlie respiration of animals. — The air expired from the lungs 
of animals contains a quantity of carbon dioxide, A^arying with the age, 
sex, food, and muscular development and activity, while, at the same time, 
a much smaller quantity is discharged by the skin and in solution in the 
urine. The following table, from the experiments of Andral and Gavar- 
ret, indicates the quantity of carbon dioxide eliminated by males of vari- 
ous ages: 

Elimination of Carbon Dioxide. 



Age. 



8 years 

15 years 

IK years 

18 to 20 years, 
20 to 524 years, 
40 to 60 years, 
60 to 80 years. 



Mean 
weight. 



In 
kilos. 



In lbs. 



22.26 49.0? 
46.41 102 82 



53.89 
60.88 
C6.90 
67.15 
63.35 



117.70 
134.22 
147.49 
148.04 
139.66 



Carbon elim- 
inated, in 
grams. 



Inl 
hour. 



5.0 
8.7 
10.8 
11.4 
12.2 
10.1 
9.2 



In 24 
hours. 



120.8 
208.8 
259.2 
273 6 
292.8 
242.4 
220.8 



Carbon diox- Oxygen ab- 



ide elimina- 
ted, in grams 



Inl 
hour. 



18.3 
31.9 
39.6 
41.8 
44.7 
37.0 
33.7 



In 24 
hours. 



442.9 

765.6 

950.4 

1003.2 

1073.6 



sorbed, 
grams. 



Inl 

hour. 



15.613 
27.166 

33.723 
35.599 
38.094 



888.8 31.537 
809.6 28.727 



In 24 

hours. 



374.70 
651 .,98 
809.36 
854.32 
914.28 
756.89 
689.45 



Carbon diox- 
ide elimina- 
ted, in litres. 



Inl 

hour. 



9.30 
16.21 
20.13 
21.25 
22.72 
18.81 
17.13 



In 24 
hours. 



225.16 
389.22 
483.17 
510.01 
545. SI 
451.85 
411.59 



Oxygen ab- 
sorbed, in 
litres. 



Inl 
hour. 



8.63 
18.91 
23.48 
24.78 
26.52 
21.95 
20.00 



In 24 

hours. 



207.22 
453. S9 
563.42 
594.79 
636.47 
5-26.92 
479.98 



In females the increase of elimination follows the same rule as with 
males until puberty, when it ceases and the amount exhaled remains 
about the same until the menopause, -when the elimination of carbon di- 
oxide suddenly increases to nearly the same as that occurring in males of 
the same age, and subsequently gradually declines with advancing age. 
During pregnancy the elimination of carbon dioxide is temporarily in- 
creased. In both sexes and at all ages the exhalation of carbon dioxide 
is greater during muscular activity than when the individual is at rest, 
and greater in those whose muscular development is more perfect. An 
adult man discharges 20.77 litres = three-fourths cubic foot of carbon di- 
oxide per hour, or 498.88 litres = eighteen cubic feet per diem. 

The expired air under ordinary conditions contains about 4.5 per cent, 
by volume of carbon dioxide, the proportion being greater the slower the 
respiration. 

Second. — Combustion. — The greater part of the atmospheric carbon 
dioxide is a product of the oxidation of carbon in some form as a source 
of light and heat. In the following table are given the amounts of 
carbon dioxide produced and of air consumed by different kinds of fuel 
and illuminating materials; by comparing them with the quantities of the 
same gases produced and consumed by an adult man it will be seen that 
in equal times an ordinary gas-burner produces nearly six times as much 
carbon dioxide and consumes nearly ten times as much air as a man. The 



CAEBOX DIOXIDE. 



239 



amount of air consumed by fuels is, for practical purposes, greater than 
that given in the table, as the oxidation is never complete, the air in the 
chimney frequently containing ten per cent, of oxygen by volume (see 
below). 

Combustion of Fuel. 





rned in 


Average per- 
centage of 


Carbon dioxide 
duced by 


pro- 


Air deoxidized by 




of 

V 

-3 

a 

a 


Fuel. 


3 
£> 

+3 
Pi 

S3 








> 




In one hour. 


"3 

> 




3 

3 



In one hour. 




T3 
S 

OS 

a 




U 








s 

3 









S 
3 


s 






CO 




a 3 




s 


4-> -A 






. 






4-1 


3 




U 3 
> ° 


3 
o 

u 

ej 


o 
u 

•a 


"3 ™ 

> % 


03 M 

c 3 


In 
kilos. 


In 

litres. 


s 

ffl 3 

s P 


" OJ 

MS 

<D 

3 


In 

kilos. 


In 

litres. 


3 

3 

ej 






< 


U 


W 


O 


0"" 






O 







w 


(J 


Hydrogen 






100.0 










2.39 


26.89 






34462 








100.0 






3.65 








9.83 






8080 








100. 








. . 






4.93 






2474 




Carbon monoxide 




42.86 




1.6 


1.57 




.... 


2.39 


0.44 






2403 








75.0 


25.00 


1.0 


2.75 






9.55 


13.45 






13063 


. . 






85.72 
40.0 


14 28 
55.0 


2.0 

0.80 


3.14 
1.67 


0.221 


112* 


14 33 
7.14 


12.67 
11.04 


1.293 


1666' 


11 857 
11000 






140 litres 




Crude petroleum 




84.0 


13.0 




3.08 


.... 


* • • • 




12.07 




• - • • 


11775 


. . 




15 gr. 


87.0 


13.0 




3.17 


0.048 


25 




12.1a 


0.235 


182 


11055 180 


Wax 


10 gr. 

10 gr. 
42 gr. 


79.2 

76.05 

70.43 

39.10 


13.2 

12.68 

10.5 

4.90 




2.89 

2.9 

2.81 

1.43 


0.029 
0.029 
0.118 


15 

15 
60 




11.24 
8.69 

8.28 

5.16 


0.146 
0.112 

0.450 


113 

86.9 
348 


10496 
9716 

3600 


100 


Stearic acid 


84 




159 










85.0 






3.10 








8 36 


.... 




7640 




Peat 




45. U 
87.0 
90.0 


1.5 
'2.5 




1 64 
3.17 
3.29 









4.82 
8.55 
9.22 


.... 




3000 
6000 




Coke 












Alcohol 




52.17 


.13. 04 




1.90 


0.037 


19 




8.64 


0.134 


104 


7183 






10 gr. C. 


•• 



Third. — Fermentation. — Most fermentations, including putrefactive 
changes, are attended by the liberation of carbon dioxide; thus, alcoholic 
fermentation takes place according to the equation: 



C 6 H, 



,0. = 



180 



2C H 6 

92 



4- SCO 
44 



2> 



and consequently discharges into the air forty-four parts by weight of 
carbon dioxide for every ninety-two parts of alcohol formed, or 191.5 litres 
of gas for every litre of absolute alcohol obtained. 

Fourth. — Tellural sources. — Volcanoes in activity discharge enormous 
quantities of carbon dioxide, and, in volcanic countries, the same gas is 
thrown out abundantly through fissures in the earth. All waters, sweet 
and mineral, hold this gas in solution, and those which have become 
charged with it under pressure in the earth's crust, upon being relieved 
of the pressure when they reach the surface, discharge the excess into 
the air. 

Fifth. — Manufacturing processes. — Large quantities of carbon dioxide 
are added to the air in the vicinity of lime- and brick-kilns, cement- 
works, etc. 



240 GENERAL MEDICAL CHEMISTRY. 

Sixth. — In mines, after explosions of "fire-damp." These explosions 
are caused by the sudden union of the carbon and hydrogen of CH 4 with 
the oxygen of the air, and are consequently attended by the formation 
of large volumes of carbon dioxide, known to miners as after-damp. 

Constancy of the amount of atmospheric carbon dioxide. — It has been 
roughly estimated by Poggendorff that 2,500,000,000,000 cubic metres of 
carbonic acid gas are annually discharged into our atmosphere, and that 
this quantity represents one eighty-sixth of the total amount at present 
existing therein. This being the case, with the present production, the 
percentage of atmospheric carbon dioxide would be doubled in eighty-six 
years; no such increase has, however, been observed, and the average 
percentage found by Angus Smith, in 1872, is about the same as that ob- 
served by Boussingault in 1840, i. e., four parts in ten thousand. The 
carbon dioxide discharged into the air is, therefor, removed from it about 
as fast as it is produced. This removal is effected in two ways: 1st, by 
the formation of deposits of earthy carbonates by animal organisms, 
corals, mollusks, etc. ; 2d, principally by the process of nutrition of vege- 
tables, which absorb carbon dioxide both by their roots and leaves, and 
in the latter, under the influence of the sun's rays, decompose it, retain- 
ing the carbon, which passes into more complex molecules; and discharg- 
ing a volume of oxygen about equal to that of the carbonic acid gas 
absorbed. 

Air contaminated with excess of carbon dioxide, and its effects upon 
the organism. — When, from any of the above sources, the air of a given 
locality has received sufficient carbon dioxide to raise the proportion 
above seven parts in ten thousand by volume, it is to be considered as 
contaminated; the seriousness of the contamination depending not only 
upon the amount of the increase, but also upon the source of the carbon 
dioxide. If the gas be derived from fermentation, or from tellural or 
manufacturing sources, it is simply added to the otherwise unaltered air, 
and the absolute amount of oxygen present remains the same; when, how- 
ever, it is produced in a confined space by the processes of combustion and 
respiration, the composition of the air is much more seriously modified, 
as not only is there addition of a deleterious gas, but a simultaneous re- 
moval of an equal volume of oxygen; hence the importance of providing, 
by suitable ventilation, for the supply of new air from without to habi- 
tations and other places where human beings are collected within doors, 
especially where the illumination is artificial. 

Although an adult man deoxidizes a little over one hundred litres of 
air in an hour, a calculation of the quantity which he would require in a 
given time cannot be based exclusively upon that quantity, as the deoxida- 
tion cannot be carried to completeness; indeed, when the proportion of car- 
bon dioxide in air exceeds five per cent., it becomes incapable of support- 
ing life, while a much smaller quantity, one per cent., is provocative of 
severe discomfort, to say the least. 

In calculating the quantity of air which should be supplied to a given 
enclosed space, most authors have agreed to adopt as a basis that the 
percentage of carbon dioxide should not be allowed to exceed 0.6 volumes 
per 1,000; of which 0.4 are normally present in air, and 0.2 the product 
of respiration or combustion. Taking the amount of carbon dioxide 
eliminated b}^ an adult at 19 litres ( = 0.7 cubic foot) per hour, a man will 
have brought the air of an air-tight space of 100 cubic metres (= 3,500 
cubic feet) up to the permissible maximum of impurity in an hour. The 
following table is given by Parkes to indicate the contamination of air 



CARBON DIOXIDE. 



241 



by the respiration of an adult in an hour, and the supply of external air 
required to restore the proper equilibrium: 







Amount of air neces- 




Amount of cubic space 
(breathing-space) for 
one man in cubic 
feet. 


Ratio per 1,000 of C0 2 
from respiration at 
the end of one hour, 
if there have been no 
change of air. 


sary to dilute to 
standard of 0.2, or 
includinginitialC02, 
of 0.6 per 1,000 vol- 
umes during the first 
hour. 


Amount necessary to 
dilute to the given 
standard every hour 
after the first. 


100 


6.00 


2,900 


3,000 


200 


3.00 


2,800 


3,000 


300 


2.00 


2,700 


3,000 


400 


1.50 


2,600 


3,000 


500 


1.20 


2,500 


3,000 


600 


1.00 


2,400 


3,000 


700 


0.85 


2,300 


3,000 


800 


0.75 


2,200 


3,000 


900 


0.66 


2,100 


3,000 


1,000 


0.60 


2,000 


3,000 



Practically, owing to the imperfect closing of doors and windows, 
and to ventilation by chimneys, inhabited spaces are never hermetically 
closed, and a less quantity of air-supply than that indicated in the table 
may usually be considered as sufficient. 

A sleeping-room occupied by a single person should have a cubic space 
of 30 to 50 cubic metres ( = 1,050 to 1,800 cubic feet), conditions which 
are fulfilled in rooms measuring 10 X 13 x 8 feet, and 13 x 15.6 x 9 feet. 

In calculating the space of dormitories to be occupied by several 
healthy people, the smallest air-space that should, under any circum- 
stances, be allowed, is 12 cubic metres (=420 cubic feet) for each person. 
To determine the number of individuals that may sleep in a room, multi- 
ply its length, width, and height together, and divide the product by 420 
if the measurement be in feet, or by 12 if it be in metres. Thus, a dor- 
mitory 40 feet long, 20 feet wide, and 10 feet high, is fitted for the ac- 
commodation of 19 persons at most, for 

40 x 20 x 10=8,000 and s^o = 19.05. 

As a rule, in places where many persons are congregated, it is neces- 
sary to resort to some scheme of ventilation by which a sufficient supply 
of fresh air shall be introduced and the vitiated air removed, the quantity 
to be supplied varying according to circumstances. Experiment has 
shown that in order to keep the air pure to the senses the quantity of air 
which must be supplied per head and per hour in temperate climates are 
as shown in table on following page. The amounts given are the small- 
est permissible, and should be exceeded wherever practicable. 

Lights. — The amounts of air to be supplied to each individual, given in 
the last section, are, with the exception of those furnished in mines, based 
upon the supposition that coal-gas is not used as a means of artificial il- 
lumination, or that the burners are so arranged with reference to the 
ventilating-flues that the products of combustion pass out immediately. 
16 



242 



GENERAL MEDICAL CHEMISTRY. 



Situation. 



Barracks (day-time 

Barracks (night-time) . . . 
Workshops (mechanical) 

School-rooms 

Hospital wards 

Hospital wards (surgical) 
Contagious and lying-in 

Mines, metalliferous 

Mines, coal 



Cubic metres. 


Cubic feet. 


35 


1,236 


70 


2,472 


70 


2,472 ■ 


35 


1,236 


85 


3,002 


170 


6,004 


170 


6,004 


150 


5,297 


170 


6,004 



Each cubic foot of illuminating-gas consumes in its combustion a quan- 
tity of oxygen equal to that contained in 7.14 cubic feet of air, and pro- 
duces 0.8 cubic feet of carbon dioxide, besides a large quantity of watery 
vapor, and less amounts of sulphuric acid, sulphur dioxide, and sometimes 
carbon monoxide; and an ordinary gas-burner consumes about three feet 
per hour. It is obvious, therefor, that a much larger quantity of pure 
air must be furnished to maintain the atmosphere of an apartment at the 
standard of 0.6 per 1,000 of carbon dioxide, when the vitiation is produced 
by the combustion of gas, than when it is the result of the respiration of a 
human being, and that to such an extent that a single three-foot burner 
requires a supply of air which would be sufficient for six human beings. 
As a basis for computation, it may be considered that, for each cubic foot 
of gas consumed, 1,800 cubic feet of air should be furnished by ventilation. 
The contamination of air by gas-lights becomes a question of serious 
importance in our dwellings upon occasions of social gatherings, and in 
theatres and other places of public resort which are used during the hours 
of darkness. The average size of a parlor in a city dwelling is 15 x 25 x 15 
feet; it therefor contains 4,875 cubic feet, and its atmosphere would, 
if it were hermetically closed, be brought to the standard of maximum 
allowable contamination by the respiration of four adults in an hour, 
allowing 1,200 cubic feet per head, per hour. If such an apartment be illu- 
minated, upon the occasion of an evening party at which fifty adults are 
present for four hours, by ten three-feet gas-burners, the amounts of air 
which should be supplied by ventilation are as follows in cubic feet. 





If the products of combustion 
of gas be discharged into the 
room. 


If the products of combustion 
of the gas be carried off. 




Per hour. 


Per hour. 


Per hour. 


For four hours. 


For ten gas-burners .... 


60,000 
54,000 


240,000 
216,000 


60.000 


240,000 


Totals 


114,000 


456,000 


60,000 


240,000 







In the first instance, in which the products of the combustion of gas 
are discharged into the apartment, an adequate ventilation can only be 



CAKBON DIOXIDE. 243 

secured by a complete change of the air every 2.6 minutes, which can 
only be attained by the use of mechanical contrivances, and with the 
production of draughts; in the second instance, in which it is presumed 
that the gas-burners are so situated, with reference to a ventilating-shaft 
or shafts, that the products of combustion are immediately carried off, 
not only is the period in which a complete change of air is required ex- 
tended to 4.8 minutes, but the heat of the burners, causing an uptake 
current in the ventilator, favors the exit of the vitiated air, and the con- 
sequent entrance of external air to take its place. 

In theatres the contamination of the air by the burning of gas should 
be entirely eliminated by placing the burners either under the dome ven- 
tilator, or in boxes which open to the air of the house only below the 
level of the burner, and which are in communication with a ventilating- 
shaft. Even under these conditions it is necessary, to ensure perfect 
ventilation, to resort to some mechanical contrivance to remove the air 
vitiated by respiration and to supply its place by fresh air from without, 
which may be previously warmed or cooled according to the season, and 
which, in cities, should be filtered. In a New York theatre, whose ven- 
tilation has been carried to such a degree of perfection that the air is 
sensibly as pure 'after as before a performance, whose cubical contents 
are about ninety thousand cubic feet, and whose seating capacity is about 
six hundred and fifty, there are injected and aspirated by two blowers, 
one in the cellar and one on the roof, one million to one million two hun- 
dred and fifty thousand cubic feet of air per hour, or about one thousand 
five hundred cubic feet per head per hour. 

When artificial illumination is obtained from lamps or candles, or from 
gas in small quantity and for a short time, the contamination of the air 
is sufficiently compensated by the ventilation through imperfect closing 
of the windows. A room without a window should never be used for 
human habitation. 

One important advantage of the electric light, if it ever become prac- 
ticable, will be that it consumes no oxygen and produces no carbon di- 
oxide. 

Although, by the combustion of fuel, oxygen is consumed and carbon 
dioxide produced, heating arrangements only become a source of vitiation 
of air under the circumstances detailed above (see p. 235); indeed, in the 
majority of cases, if properly arranged, they are means of ventilation, 
either by aspirating the vitiated air of the apartment, or by the introduc- 
tion of air from without. 

Action on the economy. — An animal introduced into an atmosphere 
of pure carbon dioxide dies almost instantly, and without entrance of 
the gas into the lungs, death resulting from spasm of the glottis, and 
consequent apnoea. 

When diluted with air, the action of carbon dioxide varies according 
to its proportion, and according to the proportion of oxygen present. 

First. — When the proportion of oxygen is not diminished, the poison- 
ous action of carbon dioxide is not as manifest, in equal quantities, as when 
the air is poorer in oxygen. An animal will die rapidly in an atmosphere 
composed of twenty-one per cent. O, fifty-nine per cent. N, and twenty 
per cent, C0 2 by volume; but will live for several hours in an atmosphere, 
whose composition is forty per cent. O, thirty-seven per cent. N, twenty- 
three per cent. C0 2 . If carbon dioxide be added to normal air, of course 
the relative quantity of oxygen is slightly diminished, while its absolute 
quantity remains the same; this is the condition of affairs existing in 



244 GENERAL MEDICAL CHEMISTRY. 

nature when the gas is discharged into the air; under these circumstances 
an addition of ten to fifteen per cent, of C0 2 renders an air rapidly poi- 
sonous, and one of five to eight per cent, will cause the death of small 
animals more slowly. Even a less proportion than this may become fatal 
to an individual not habituated. 

In the higher states of dilution, carbon dioxide produces immediate 
loss of muscular power, and death without a struggle; when more dilute, 
a sense of irritation of the larynx, drowsiness, pain in the head, giddi- 
ness, gradual loss of muscular power, and death in coma. 

Second. — If the carbon dioxide present in air be produced by respi- 
ration or combustion, the proportion of oxygen is at the same time di- 
minished, and much smaller absolute and relative amounts of the poison- 
ous gas will produce the effects mentioned above; thus, an atmosphere 
containing in volumes 19.75 per cent. O, 74.25 per cent. N, six per cent. 
C0 2 , is much more rapidly fatal than one composed of twenty-one per 
cent. O, fifty-nine per cent. N, twenty per cent. C0 2 . With a corre- 
sponding reduction of oxygen, five per cent, of carbon dioxide renders an 
air sufficiently poisonous to destroy life; two per cent, produces severe 
suffering; one per cent, causes great discomfort, while 0.1 per cent., 
or even less, is recognized by a sense of closeness. 

The treatment in all cases of poisoning* by carbon dioxide consists in 
the inhalation of pure air (to which a small excess of oxygen may be 
added), aided, if necessary, by artificial respiration, the cold douche, gal- 
vanism, and friction. 

When it chances that an individual entering an atmosphere contain- 
ing an excess of carbon dioxide, or other noxious gas, is seen to fall in- 
sensible, it is simply multiplying the number of victims, for others to fol- 
low, unprotected, with a view to effecting a rescue. Probably the most 
readily obtainable protection is a towel saturated with lime-water, and so 
held over the mouth and nostrils that the inspired air passes through it, 
and also through two or three layers of dry towelling interposed between 
the moistened part and the skin. Obviously this protection will not be 
efficacious for a long time, and in situations where such accidents are 
liable to occur, as in mines, fermenting cellars, etc., it cannot be too 
strongly recommended that there be kept at hand air-pumps, tubing, and 
helmets, such as are used by divers, but of lighter construction, to be 
used by the rescuers upon such occasions. 

Detection of carbon dioxide and analysis of confined air. — Carbon 
dioxide, or air containing it, causes a white precipitate when caused to 
bubble through lime or baryta water; normal air contains enough of the 
gas to form a scum upon the surface of these solutions when exposed to it. 

It was at one time supposed that air in which a candle continued to 
burn was also capable of maintaining respiration. This is, however, by 
no means necessarily true; a candle introduced into an atmosphere in 
which the normal proportion of oxygen is contained, burns readily in the 
presence of eight per cent, of carbon dioxide; is perceptibly dulled by 
ten per cent.; is usually extinguished with thirteen per ceut. ; always 
extinguished with sixteen per cent. Its extinction is caused by a less 
proportion of carbon dioxide, four per cent., if the quantity of oxygen 
be at the same time diminished. Moreover, a contaminated atmosphere 
may not contain enough carbon dioxide to extinguish, or perceptibly dim 
the flame of a candle, and at the same time contain enough of the mon- 
oxide to render it fatally poisonous if inhaled. 

The presence of carbon dioxide in a gaseous mixture is determined by 



SULPIIOCAKBOKIC ACID. 245 

its absorption by a solution of potassium hydrate; its quantity either by 
measuring- the diminution in bulk of the gas, or by noting- the increase in 
weight of the alkaline solution. 

To determine the proportions of the various gases present in air, it is 
made to pass through a series of tubes which have been previously 
weighed: 1st, through a U-shaped tube containing fragments of pumice- 
stone, saturated with sulphuric acid; by the increase in weight of this 
tube the amount of water}' vapor is determined; 2d, through a Liebig's 
bulb-apparatus, filled with a solution of potassium hydrate. The ra- 
pidity of the current should be so regulated that about thirty bubbles 
a minute pass through this apparatus; 3d, through a U-tube filled with 
fragments of pumice saturated with sulphuric acid. Numbers two and 
three are weighed together, the increase in their weight is the weight of 
C0 2 in the volume of air drawn through the apparatus; every gram of 
increase in weight represents 0.50607 litre, or 31.60356 cubic inches. 

The arrangement of the remainder of the absorption apparatus differs 
according to whether carbon monoxide and marsh-gas, or oxygen, is to be 
determined. In the former case the air is next passed; 4th, through a 
tube of difficultly fusible glass, filled with black oxide of copper, and 
heated to redness, in which the gases mentioned are converted into water 
and carbon dioxide; then oth, through a U-tube filled with pumice, 
moistened with sulphuric acid, whose increase of weight indicates the 
amount of water so formed. Every gram of increase of weight in this 
tube represents 0.444 gram, or 0.621 litre, or 38.781 cubic inches of marsh- 
gas. Finally, the gas is passed, 6th, through a carbon dioxide apparatus, 

similar to numbers two and three, from whose increase in weight the 

• t • t 
quantity of carbon monoxide is calculated, thus: first, 2.75 grams are 

deducted for each gram of marsh -gas found by number five; of the re- 
mainder, every gram represents 0.6364 grams, or 0.5085 litre, or 31.755 
cubic inches of carbon monoxide. 

If the percentage of oxyg'en is to be determined, the gas, after passing 
from No. 3, is collected in a graduated tube and its volume measured; a 
concentrated solution of potassium pyrogallate is passed into the tube, 
which is agitated without removing its opening from the trough, allowed 
to stand, and the volume again determined; the difference in volume is 
the quantity of oxygen in the original volume of air. In both measure- 
ments the level of liquid in the tube must be the same as that in the trough. 

To draw the air through the absorbing apparatus, an aspirator is used, 
and the volume of air determined by the volume of escaping water. 



Sulphoearbonic Acid, Cs/I^' 

is of interest as corresponding in constitution to the hypothetical carbonic 
acid, sulphur replacing oxygen, but, unlike that acid, being capable of 
existing free. It may be obtained by treating an alkaline sulphocarbo- 
nate with hydrochloric acid and immediately afterward with water, as a 
reddish brown oily liquid, which is insoluble in water, and readily decom- 
posable into carbon disulphide and hydrogen sulphide. 



246 GENERAL MEDICAL CHEMISTRY. 



Carbon Disulphide. 

bisulphide of carbon, CS 2 . — This substance, which bears the same rela- 
tion to sulphocarbonic acid and the sulphocarbonates that carbon dioxide 
does to the hypothetical carbonic acid and to the carbonates, does not exist 
in nature. It is obtained by passing the vapor of sulphur over carbon heated 
to redness, and partially purified by rectification. It is further purified 
by agitation and twenty-four hours' contact with one-half per cent, of 
powdered mercuric chloride, decantation, treatment with two per cent, 
of an odorless fatty material, and slow distillation. 

The pure product is a colorless liquid, which has a peculiar, but not 
disagreeable, ethereal odor; the nauseating odor of the commercial bisul- 
phide is due to the presence of another sulphuretted body; boils at 47°; 
sp.gr. 1.293; very volatile; its rapid evaporation in vacuo produces a 
temperature of — 60°; it does not mix with water, through which it falls 
in globular drops. It refracts light strongly, and is used to fill prisms used 
in some forms of spectroscopic apparatus. 

It is highly inflammable, and burns with a bluish flame, giving off car- 
bon dioxide and sulphur dioxide; its vapor forms highly explosive mix- 
tures with air, which detonate on contact with a glass rod heated to 250°. 
Its vapor forms a mixture with nitrogen dioxide, which, when ignited, 
burns with a brilliant flame, rich in actinic rays. 

There also exists a substance intermediate in composition between 
carbon dioxide and carbon disulphide, known as carbon oxysulphide, CSO, 
which is an inflammable, colorless gas, obtained by decomposing potassium 
sulphocyanate with dilute sulphuric acid. 

Carbon disulphide is now manufactured in large quantities, and is used 
in the arts to dissolve the ordinary phosphorus, remaining as an impurity 
in the preparation of the red variety, as a solvent of sulphur and india-rub- 
ber, and for the extraction of fats and oils, which it dissolves freely. 

Toxicology. — Cases of acute poisoning by carbon disulphide have 
hitherto only been observed in animals; its action is very similar to that 
of chloroform. 

Workmen engaged in the manufacture of carbon disulphide and in 
the vulcanization of rubber, as well as others exposed to the vapor of the 
disulphide,. are subject to a form of chronic poisoning which may be di- 
vided into two stages. The first, or stage of excitation, is marked by 
headache, vertigo, a disagreeable taste, cramps in the legs; the patient 
talks, laughs, sings, and weeps immoderately, and sometimes becomes 
violently delirious. In the second stage the patient becomes sad and 
sleepy, sensibility diminishes sometimes to the extent of complete anaes- 
thesia, especially of the lower extremities, the headache becomes more in- 
tense, the appetite is greatly impaired, and there is general weakness of 
the limbs, which terminates in paralysis. 

The only remedy which has been suggested is through ventilation of 
the workshops and abandonment of the trade at the first appearance of 
the symptoms. 

CH 2 OH 
Glycollio Acid, | , 

COOH 

is formed by the oxidation of glycol, by the action of nitrous acid upon 
glvcocol, and by the action of potassium hydrate upon monochloracetic 
acid. 



LACTIC ACIDS. 247 

It forms deliquescent, acicular crystals; very soluble in water; soluble 
in alcohol and ether; has a strongly acid taste and reaction; fuses at 78°; 
is decomposed at 150°; at an intermediate temperature it loses H 2 0, form- 
ing gly collide, or glycollic anhydride, C 2 H 2 2 . 

It is a monobasic acid. The hydrogen of the group CH 2 OH may be 
replaced by an alcoholic radical to form other acids, such as amylglycollic 

CH a O,C 6 H n 
acid, | 

COOH 

Lactic Acids, C 3 H 6 3 . 

There are probably three, certainly two, acids having this composi- 
tion, which differ from each other mainly in the products of their decom- 
position, in their physical properties, and in the solubility and amount of 
water of crystallization of their salts. They resemble each other in being 
colorless, syrupy liquids; insoluble in water, alcohol, and ether, and very 
acid in taste and in reaction. 

Two of these acids would seem, from their products of decomposition, 
to be of similar constitution, while the molecular composition of the third 
is distinct; the two of similar composition are sometimes designated as 
ethylidene lactic acids, because of their containing the group of atoms 
CH 3 , while the third is designated as ethyleno-lactic acid, as it contains 
the group CH a ; the composition is expressed by the formulae: 

CH 3 CH 2 OH 

I I 

CH,OH CH 2 



I 



COOH COOH 

Ethylidene lactic acid. Ethyleno-lactic acid. 

Obviously it is the ethylene acid which is the superior homologue of gly- 
collic acid. 

Ethyleno-lactic acid. — As early as 1807 Berzelius discovered in muscu- 
lar tissue an acid which he took to be lactic acid, but which was subse- 
quently shown by Liebig to differ from it in several of its characters. 
The latter chemist suggested the name of sarcolactic acid, which it has 
retained until recent researches have shown that the name must be 
abandoned, as the acid in question is a mixture of two distinct acids — 
ethyleno-lactic and optically active ethylidene lactic acid — both of which 
differ from the ordinary lactic acid of fermentation. 

Ethyleno-lactic acid may be obtained from muscular tissue, or better, 
from Liebig's extract of meat, by a process described below (see p. 248). 
It may also be obtained synthetically by a process which indicates its con- 
stitution and the rationale of its name. By the action of potassium 
cyanide upon ethylene chlorhydrate, the nitrite of the ethyleno-lactic acid 
is formed: 



CH 2 ,C1 + ON) = 
CH 2 ,OH K J" 


CH 2 -CN 
CII 2 -0H 


+ k[ 


Ethylene Potassium 
chlorhydrate, cyanide. 


Cyanhydrin. 


Potassium 
chloride. 



248 



GENERAL MEDICAL CHEMISTRY. 



The cyanhydrine so obtained, when acted upon by caustic potassa, is 
decomposed with elimination of ammonia and formation of potassium 
ethyleno-lactate : 



CN 



EL 



A 



H,OH 

Oyanhydrin. 



+ 



H 
K 



O + 



Potassium 
hydrate. 



H 
H 







Water. 



COOK 

I 
= CH, + NH, 



CH 2 OH 

Potassium 
ethyleuo-lactate. 



Ammonia. 



It is distinguished by the following characters: it is optically inactive, 
as are also solutions of its salts; its zinc salt contains two molecules of 
water of crystallization, and is very soluble in water and quite soluble in 
alcohol. When oxidized by chromic acid this acid yields malonic acid, as 
would be expected from an examination of the formulae of the two acids: 



CH 2 ,OH 



CET 



CO,OH 

I 
CET 



A 



0,OH 

Ethyleno-lactic acid. 



i 



!0,0H 

Malonic acid. 



Of the two ethylidene lactic acids, that which is optically active is the 
one accompanying ethylene lactic acid, and predominating over it in 
amount in dead muscle; it is to this acid that the name par atactic acid 
is most properly applied. 

It may be obtained from Liebig's meat extract; this is dissolved in 
four parts water; eight parts strong alcohol are then added during con- 
stant agitation; after standing, the clear liquid is decanted off, and the 
insoluble residue again extracted with two parts of warm water, and the 
solution precipitated with four parts strong alcohol. The united alcoholic 
fluids are evaporated to a thin syrup over the water-bath, and the residue 
again precipitated with four volumes of strong alcohol; the clear alco- 
holic fluid is evaporated to dryness; the residue extracted with water; the 
solution acidulated with dilute sulphuric acid and shaken with successive 
portions of ether. The ethereal fluid, on evaporation, leaves a mixture of 
this acid and ethyleno-lactic acid, which is dissolved in water; the solu- 
tion is boiled with zinc oxide, filtered, the filtrate evaporated until crys- 
tals begin to form, when four or five volumes of strong alcohol are added 
and the mixture set aside; zinc paralactate crystallizes at first, and is 
thus separated from the ethyline lactate, which is much more soluble. 
From the zinc salts the acids are obtained by solution in water, decom- 
position by hydrogen sulphide, filtration, concentration, extraction with 
ether, and evaporation of the ethereal solutions. 

Paralactic acid differs from its two isomeres in that its solutions are 
dextrogyrous, and the solutions of its salts are laevogyrous. The specific 
rotary power of the acid is [«]„= +3.5°; that of the zinc salt [a] D = 
— 7.6°; and of the calcium salt [a] D = — 3.8°. 

Its products of decomposition are the same as those of ordinary lactic 
acid. 



LACTIC ACIDS. 249 

Ordinary lactic acid — Lactic acid of fermentation — Optically inac- 
tive ethylidene lactic acid — exists in nature, widely distributed in the 
vegetable kingdom, and, as its name implies, as the product of a fermen- 
tation which is designated as the lactic, in milk, sour-krout, fermented 
beet-juice, and rice, and in the liquid refuse of starch-factories and tan- 
neries. 

Lactic acid is obtained as a product of the fermentation of certain 
sugars, milk-sugar and grape-sugar, as a result of the processes of nutri- 
tion of a minute vegetable, the lactic ferment, in which the sugar is con- 
verted into its polymere: 

C,H„O a = 2C,H 6 3 

Grape-sugar. Lactic acid. 

The process usually followed consists in allowing a solution composed 
of cane-sugar, 3 kilos, tartaric acid, 15 grams, water, 13 kilos, to stand 
several days; 60 grams of rotten cheese, mixed with 4 kilos skimmed milk 
and 1^ kilos washed chalk, are then added, and the mass exposed to a 
temperature of 30° — 35° for ten days, being stirred from time to time; 
10 kilos of boiling water and 15 grams of slacked lime are then added; 
the liquid is filtered through a cloth, concentrated, and allowed to crystal- 
lize; the calcium lactate so obtained, purified by recrystallization, is dis- 
solved in water and decomposed by an equivalent quantity of sulphuric 
acid; the clear watery fluid is neutralized with zinc carbonate. The zinc 
lactate so formed is purified by recrystallization, decomposed with hydro- 
gen sulphide, and the liberated lactic acid separated by filtration and con- 
centration of the watery liquid. 

It has also been obtained synthetically by oxidation of the propylglycol 
of Wurtz, which is a secondary glycol, a synthesis which indicates its 
constitution: 



CH S CH 3 

I I 

CHOH + O, = CHOH -f H,0 



CH 2 OH COOH 

ropylglycol. Oxygen; Lactic acid. Water. 

It is a colorless, syrupy liquid; sp. gr. 1.215 at 20°; does not solidify 
at — 24°; soluble in water, alcohol, and ether; is not capable of distillation 
without decomposition; when heated to 130° it loses water and is con- 
verted into dilactic acid, C 6 H 10 O 6 , and, when heated to 250°, into lactide, 
C 3 H 4 2 . It is a good solvent of tricalcic phosphate. 

Oxidizing" agents convert this acid into formic and acetic acids without 
the formation of any malonic acid. 

Physiological. — The three lactic acids are widely disseminated in ani- 
mal nature, either free or in combination. Free lactic acid of fermenta- 
tion occurs in the contents of the small intestine, and, when vegetable 
food has been taken, in the stomach; it is not, however, the acid to which 
the normal, unmixed gastric juice owes its acidity. Its salts have been 
found to exist in the contents of the stomach and those of the intestines, 
chyle, bile, parenchymatous fluid of spleen, liver, thymus, thyroid, pan- 
creas, lungs, and brain; urine. Pathologically in the blood in leucocy- 
thasmia, pyremia, puerperal fever, and after excessive muscular effort; in 



250 



GENERAL MEDICAL CHEMISTRY. 



the fluids of ovarian cysts and transudations. In the urine it is abundant 
in phosphorus-poisoning, in acute atrophy of the liver, and in rachitis and 
osteomalachia. 

Muscular tissue, after death or continued contractions, contains the 
mixture of acids known to the older authors as sarcolactic acid. Normal, 
quiescent muscle is neutral in reaction; but, as soon as rigor mortis appears, 
or if the muscle be tetanized, its reaction becomes acid from the liberation 
of sarcolactic acid. Whether these acids are formed de novo during the 
contraction of the muscle, or whether they are produced by the decom- 
position of lactates existing in the quiescent muscle, is still undetermined; 
certain it is, however, that a given quantity of muscle has, when separated 
from the circulation, a fixed maximum of acid-producing capacity, which 
is greater in a muscle that has been tetanized during the interval between 
its removal and the establishment of rigor, than in one which has been 
at rest. 

There exist no grounds upon which to base the supposition that, in 
rheumatic fever, lactic acid is present in the blood. 

The remaining acids of this series are not of sufficient practical inter- 
est to warrant further consideration. 



DIATOMIC AND DIBASIC ACIDS, 



Series C n H 2n _ 2 4 . 
The acids of this series at present known are: 



Oxalic acid C 2 4 H 2 

Malonic acid C 3 4 H 4 

Succinic acid C 4 4 H 6 

Deoxyglutanic acid . C5O4H8 



Adipic acid C 6 O 4 H 10 

Pimelic acid C 7 4 Hia 

Suberic acid C b 4 Hi 4 



Azelaic acid .C 9 4 Hi 8 

Sebacic acid Ci O 4 H 18 

Roccellic acid Ci70 4 H 3a 



They are derived from the primary glycols by complete oxidation; 
they are diatomic and dibasic, and contain two groups, CO, OH. They 
form two series of salts with the univalent metals, and two series of 
ethers, one of which contains neutral, and the other acid ethers. They 
may be obtained from the corresponding glycols, or acids of the preceding 
series, by oxidation. 



Oxalic Acid, 



CO,OH 
CO,OH : 



exists in the oxalates of potassium, sodium, calcium, magnesium, and 
iron; in the juices of many plants, notably in sorrel, rhubarb, cinchona, 
oak, etc.; as a native ferrous oxalate — humboldtine; and in small quan- 
tity in human urine. 

It was formerly obtained from the vegetables in which it exists, but 
is now artificially prepared, either by oxidizing sugar or starch by nitric 
acid, or by the action of an alkaline hydrate in a state of fusion upon 
sawdust, by which an alkaline oxalate is produced. The soluble alkaline 
salt is converted into the insoluble calcium or lead oxalate, which is 
washed and decomposed with an equivalent quantity of sulphuric acid or 



OXALIC ACID. 251 

with hydrogen sulphide; the liberated oxalic acid is purified by recrystal- 
lization. The product so obtained is sufficiently pure for industrial pur- 
poses, but is still contaminated with small quantities of potassium sul- 
phate and oxalate, and calcium oxalate, to separate which, when the acid 
is required pure, as for volumetric analysis, the commercial acid is re- 
peatedly recrystallized from water and from alcohol. 

Oxalic acid is also formed in a number of other reactions: by the oxi- 
dation of many organic substances — alcohol, glycol, sugar, etc.; by the 
action of potassa in fusion upon the alkaline formiates; and by the action 
of potassium or sodium upon carbon dioxide. 

It crystallizes in transparent prisms, containing two molecules of water 
of crystallization, which effloresce on exposure to air, and lose their water 
slowly but completely at 100°, or in a dry vacuum. It fuses at 98° in its 
water of crystallization; at 110° — 132° it sublimes in the anhydrous form, 
while a portion is decomposed; above 160° the decomposition is more 
extensive; water, the two oxides of carbon and formic acid, are produced, 
while a portion of the acid is sublimed unchanged. It dissolves in 15.5 
parts of water at 10°; in 9.5 parts at 14°, and in a smaller quantity of 
boiling water; the presence of nitric acid increases its solubility. It is 
quite soluble in alcohol. It has a sharp taste and an acid reaction in 
solution. 

Oxalic acid is quite readily oxidized; in watery solution it is converted 
into carbon dioxide and water, slowly by simple exposure to air, more 
rapidly, in the presence of platinum black or of the salts of platinum and 
gold, under the influence of sunlight, or when heated with nitric acid, 
manganese dioxide, chromic acid, bromine, chlorine, or hypochlorous acid. 
Its oxidation, when it is triturated dry with pure oxide of lead, is suffi- 
ciently active to heat the mass to redness. Sulphuric and phosphoric acids 
and other dehydrating agents decompose it into water and the two oxides 
of carbon. 

Oxalic acid, or the soluble oxalates, in neutral or alkaline solution, 
gives a white precipitate of calcium oxalate with any soluble calcium salt. 
The oxalates of silver and lead, and mercurous oxalate, are also insoluble 
or very sparingly soluble in water. 

Uses. — Oxalic acid is largely used in the arts, in dyeing and calico 
printing; to clean copper utensils; and to remove stains of iron-rust or of 
ink. It was at one time used in medicine, but its use has been abandoned. 

Toxicology. — Although certain oxalates are constant constituents of 
vegetable food and of the human body, the acid itself, as well as hydro- 
potassic oxalate, is a violent poison when taken internally, acting both 
locally as a corrosive upon the tissues with which it comes in contact, 
and as a true poison, the predominance of either action depending upon 
the concentration of the solution. Dilute solutions may produce death 
without pain or vomiting, and after symptoms resembling those of narcotic 
poisoning. Death has followed a dose of 3 ]*• of the solid acid, and re- 
covery a dose of § j. in solution. When death occurs, it may be almost 
instantaneously, usually within half an hour; sometimes after weeks or 
months, from secondary causes. 

The treatment, which must be as expeditious as possible, consists in 
the administration, Jirst, of lime or magnesia, or a salt of calcium or mag- 
nesium suspended or dissolved in a small quantity of water or mucilagi- 
nous fluid; afterward, if vomiting have not occurred spontaneously, and 
if the symptoms of corrosion have not been severe, an emetic may be 
given. In the treatment of this form of poisoning several points of nega- 



252 GENERAL MEDICAL CHEMISTRY. 

tive caution are to be observed. As in all cases in which a corrosive has 
been taken internally, the use of the stomach-pump is to be avoided. 
The alkaline carbonates, which may be used as antidotes when the min- 
eral acids have been ingested, are of no value in cases of oxalic acid poi- 
soning 1 , as the oxalates which they form are soluble, and almost as poison- 
ous as the acid itself. The ingestion of water, or the administration of 
warm water as an emetic, is contraindicated when the poison has been 
taken in the solid form (or where doubt exists as to what form it was 
taken in), as they dissolve, and thus favor the absorption of the poison. 

Analysis. — In fatal cases of poisoning by oxalic acid the contents of 
the stomach are sometimes strongly acid in reaction; more usually, owing 
to the administration of antidotes, neutral, or even alkaline. In a sys- 
tematic analysis the poison is to be sought for in the residue of the por- 
tion examined for prussic acid and phosphorus; or, if the examination 
for those substances be omitted, in the residue or final alkaline fluid of 
the process for alkaloids (see p. 348 et seq.). If oxalic acid alone is 
to be sought for, the contents of the stomach, or other substances if acid, 
are extracted with water, the liquid filtered, the filtrate evaporated, the 
residue extracted with alcohol, the alcoholic fluid evaporated, the residue 
redissolved in water (solution No. 1). The portion undissolved by al- 
cohol is extracted with alcohol acidulated with hydrochloric acid, the 
solution evaporated after filtration, the residue dissolved in water (so- 
lution No. 2). Solution No. 1 contains any oxalic acid which may 
have existed free in the substances examined; No. 2 that which existed 
in the form of soluble oxalates. If lime or magnesia have been admin- 
istered as an antidote, the substances must be boiled for an hour or two 
with potassium carbonate (not the hydrate), filtered, and the filtrate 
treated as above. In the solutions so obtained, oxalic acid is character- 
ized by the following 

Tests. — Silver nitrate forms a white precipitate, readily soluble in 
nitric acid and in ammonia. The precipitate does not darken when the 
fluid is boiled, but, when dried and heated on platinum foil, it explodes. 
Lime-water or solution of calcium chloride or sulphate, form a white pre- 
cipitate, insoluble in water, almost so in acetic and oxalic acid; readily 
soluble in hydrochloric or nitric acid. The formation of this precipitate 
in dilute solutions is favored by a previous addition of ammonium hydrate. 

Lead acetate, in not too dilute solutions, produces a white precipitate, 
soluble in nitric, insoluble in acetic acid. 

In toxical analyses it must not be forgotten that small quantities of 
oxalates may be introduced into the stomach as normal constituents of 
the food. 

In cases of suspected poisoning by oxalic acid, the urine should be 
examined microscopically for crystals of calcium oxalate. 



CO,OH 

I 
Malonie Acid, CH 3 , 

CO,OH 

is of interest as a product of oxidation of the corresponding acid of 
the preceding series, ethyleno-lactic acid, and as being identical with an 
acid obtained from tobacco, and designated as nicotic acid. 



SUCCINIC ACID. 253 

It crystallizes in prismatic needles; which fuse at 140°, are decomposed 
at 150°; and are very soluble in water, alcohol, and ether. 



CH — CO,OH 
Succinic Acid, j , 

CH— CO,OH 

was one of the first organic acids known to chemists. It exists in nature 
in amber, coal, fossil wood, and in small quantities in animal and vege- 
table tissues. Its presence has been detected in the normal urine after 
the use of fruits and of asparagus, in the parenchymatous fluids of the 
spleen, thyroid, and thymus, and in the fluids of hydrocele and of hydatid 
cysts. It is also formed in small quantity during alcoholic fermentation. 
It is formed as a product of oxidation of many fats and fatty acids; and 
by synthesis from ethylene cyanide. 

It may be obtained by dry distillation of amber, or, preferably, by the 
fermentation of malic acid. One kilo of calcic malate is dissolved in three 
kilos of water, and to the solution eighty grams of stale cheese, or 250 
c.c. of yeast, are added. The mass is exposed to a temperature of 30° — 
40°, for Ave to six days, when succinic acid is formed according to the 
equation: 

3C 4 H 6 5 = 2C 4 H 6 4 + C 2 H 4 2 + 2C0 2 + H 2 

Malic acid. Succinic acid. Acetic acid. Carbon dioxide. "Water. 

A mixture of calcium succinate and carbonate crystallizes out, is washed, 
sulphuric acid added as long as effervescence occurs, the mass extracted 
with water, sulphuric acid added as long as a precipitate is formed, the 
solution filtered, and the succinic acid allowed to crystallize out. 

It crystallizes in large prisms or hexagonal plates, which are colorless, 
odorless, permanent in air, acid in taste, soluble in water, sparingly so in 
ether and in cold alcohol. It fuses at 180°, and distils with partial de- 
composition at 235°. 

Succinic acid withstands the action of oxidizing agents; reducing 
agents convert it into the corresponding acid of the fatty series, butyric 
acid; with bromine it forms products of substitution; sulphuric acid is 
without action upon it; phosphoric anhydride removes the elements of a 
molecule of water and converts it into succinic anhydride, C 4 H 4 3 . 

The remaining acids of this series may be dismissed with a few words. 

Deoxyglutanic acid, C 5 H 8 4 — is derived from glutanic acid by heating 
with hydriodic acid. It forms large crystals, soluble in water. It is iso- 
meric with pyrotartaric acid. 

Adipic acid, C 6 H 10 O 4 — is formed by the action of nitric acid upon 
many fatty substances; it bears the same relation to leucic acid that oxalic 
does to glycolic acid. It is soluble in water, alcohol, and ether; fuses at 
130°. 

Pimelic acid, C 7 H 12 4 — is another product of the oxidation by nitric 
acid of fatty substances, notably of oleic acid. It forms small crystals; 
sparingly soluble in water, alcohol, and ether; quite soluble in the same 
liquids when hot. 

Suberic acid, C 8 H 14 4 — a product of the oxidation, by nitric acid, of 
cork, oleic, and stearic acids, and oils containing them. It forms small 



254 GENERAL MEDICAL CHEMISTRY. 

crystals, sparingly soluble in cold water, readily soluble in hot water, al- 
cohol, and ether. 

Azelaic acid, C 9 H 16 4 — also known as anchoic acid, is formed, along 
with the preceding, by oxidation of castor-oil. 

Sebacic acid, 10 H 18 O 4 — is a product of the decomposition of oleic acid 
by dry distillation, and of the action of potash on castor-oil. It crystal- 
lizes in pearly needles; fusible at 126°; sparingly soluble in cold water, 
readily soluble in hot water, alcohol, and ether. 

JRoccellic acid, C 17 H 32 4 — exists in various lichens, roccella tinctoria, 
fuciformis, etc., from which litmus and orchel are prepared. It crystal- 
lizes in colorless c^stals; fusible at 132°; insoluble in water; soluble in 
alcohol and in ether. 



COMPOUND ETHERS OF THE ACIDS OF THE SERIES 

C n H 2n 3 and C n H 2n _ 2 4 . 

The members of both of these series contain two atoms of hydrogen 
replaceable by alcoholic radicals. In those of the series n H 2n O 3 , with the 
exception of carbonic acid, being monobasic, although diatomic, it is not 
immaterial which hydrogen is so replaced; if it be that of the group 
CH 2 OH, the resulting compound is a monobasic acid, in which the hydro- 
gen of the group COOH may be replaced by another alcoholic radical to 
form a neutral ether of the new acid; if, on the other hand, the hydrogen 
of the group COOH be first replaced, a neutral compound ether is formed. 
In the members of the series C n H 2n _ 2 4 , which are dibasic, the substitu- 
tion of an alcoholic radical for the hydrogen of either group COOH pro- 
duces a monobasic acid, in which the hydrogen of the other COOH may 
be replaced by another radical to form a neutral ether. The following 
formulae indicate the differences in the nature of these compounds: 

CH„OH CH 2 OC 2 H 6 CH 2 OH CH 2 OC 2 H 5 



A, 



COOH COOH COOC 2 H B COOC 2 H 5 

Gly colic acid Ethylgly colic acid. Ethyl glycolate. Ethyl ethylglycolate. 

COOH COOCJL COOCH B 

I I I 

COOH COOH COOC 2 H 5 

Oxalic acid. Ethyloxalic acid. Ethyl oxalate. 

None of the many ethers of these series are of medical interest. 



ALDEHYDES AND ANHYDRIDES OF THE SERIES 

C H H 2H 3 and C n H 2H _ 2 4 . 

In treating of the monoatomic compounds, it was stated that sub- 
stances existed corresponding to the fatty acids, known as aldehydes and 
anhydrides, the former differing from the acids in that they contained the 
group COH instead of COOH, the latter being the oxides of the acid 
radicals. Similar compounds exist corresponding to the acids of these 
two series. 



AMINES OF THE GLYCOLS. 255 

The aldehydes corresponding to the series C n H 2 „0 3 contain the group 
COH in place of the group COOH, and as they also contain the group 
CH 2 OH, they are possessed of the double function of primary alcohol and 
aldehyde. Those of the series C„H 2n _ 2 4 form two series; in one of which 
only one of the groups COOH is deoxidized to COH; in the other, both. 
Those of the first series, still containing a group COOH, are monobasic 
acids as well as aldehydes: 

CHOH CHOH COOH COOH COH 

I I I I I 

COOH COH COOH COH COH 

Glycolic acid. Glycolic aldehyde. Oxalic acid. Glyoxalic acid. Glyoxol. 

While the anhydrides of the fatty series may be considered as derived 
from the acids by the subtraction of the elements of a molecule of water from 
two molecules of the acids, those of both the series of acids under consider- 
ation are derived from a single molecule of the acid by the subtraction of 
the elements of a molecule of water: 



A 



CH. CH — (XX CH 2 OH 

>0 | 

OOH CH 3 — CO/ COOH 

Acetic acid. Acetic anhydride. Glycolic acid. 

CH 2V CH— COOH CH— CO. 

CO / CH— COOH CH — CO/ 

Glycolic anhydride. Succinic acid. Succinic anhydride. 

None of those substances are of practical medical importance. 



AMINES OF THE GLYCOLS. 

Ethtlenic Compound Ammonias. 

These substances are derived from a double molecule of ammonia, or 
of ammonium hydrate, by the substitution of the diatomic radicals of the 
glycols (hydrocarbons of the series C n H 2n ) for an equivalent number of 
hydrogen atoms. They are distinguished from the corresponding com- 
pounds of the radicals of the monoatomic alcohols, the monamines^ by the 
designation of diamines. 

When it is considered that in the formation of these substances double 
hydrogen atoms can be replaced by diatomic radicals to form primary, 
secondary, and tertiary amines: 

HJ (0,H,)") (0,H 4 V'l (C,H,)» 

H, N, H, N, C,HJ"K (C,H,)"N, 



HJ H, ) H, (0 S H,)" 



Double ammonia Ethylene amine. Dlethylene amine. Triethylene amine. 

molecule. Primary, Secondary* tertiary. 

that others exist in which two univalent radicals replace a divalent rad- 
ical; others, again, in which atoms of hydrogen have been replaced by 
groups OH; and finally, that similar compounds of phosphorus, arsenic, 



256 GENERAL MEDICAL CHEMISTRY. 

and antimony exist, it is not astonishing that the study of the vast num- 
ber of substances, the possibility of whose existence is thus indicated, is 
still in its infancy. 

Although at present we know of none of these substances which is of 
medical interest, there is strong probability that further investigation will 
show some of the natural alkaloids, whose constitution is as yet unknown, 
to belong in this class. 



AMIDES OF THE ACIDS OF THE SERIES 

C n H 2n 3 AND C n H 2 n- 2 4 . 

This class of substances, formed by the substitution of radicals of the 
acids for atoms of hydrogen in ammonia molecules, contains some sub- 
stances of the greatest medical interest. The radicals of the acids of the 
series C n H„ n 3 , except carbonic acid, being univalent, form amides similar 
in constitution to those of the acids of the series n H 2n Q (p. 207). 

In the case of the dibasic acids no less than three series of amides are 
known to exist; thus we have, corresponding to oxalic acid: 



co v 

1 \ 


CO. 

1 > 

CCKN, 


COOH 
1 


COOH 


1 n 

CO / 


cox 




H 5 X 


H— N 


COOH 


H„X 


H/ 




Oximide. 


Oxamide. 


Oxamic acid. 


Oxalic acid. 


Secondary monamide. 


Primary diamide. 


Primary mojiamide. 


Acid. 



In the first of these, two atoms of hydrogen of a single molecule of 
ammonia are replaced by the divalent radical of the acid; these are dis- 
tinguished as imides. Those of the second series are normally formed 
diamides. In the third series, the univalent remainder, left by the re- 
moval of OH from the acid, replaces an atom of hydrogen in one molecule 
of ammonia, and the resulting compound, still containing a group COOH, 
has the functions of a monobasic acid. 



Amides of Carbonic Acid. 
Carbimide, (C0 ^N. 

Although many chemists have regarded cyanic acid (q. v.) as being 
the imide of carbonic acid, there are many reasons, drawn from the methods 
of formation and properties of cyanic acid, which lead us to assign to it 

CN 
the constitution j , rather than that given above, and to consider it as 

OH 
the isomere of the hitherto undiscovered carbimide. 



CAEB AMIDE UREA. 257 



(CO)" 
Carbamide — Urea, H 2 J- N . 

H s 

This important substance, whose existence was suspected by Boerhaave 
and Haller, was first obtained in an impure form by the younger Iiouelie, 
in 1771, who called it extractum saponaceum urinoe; and in a state of 
comparative purity by Oruikshank in 1798. The name urea was given it 
in 1799, by Fourcroy and Vauquelin. It is of great interest, historically 
as well as medically, as being the first in the great catalogue of organic 
substances that have been obtained by synthetic methods, its synthesis 
having been effected by Woehler in 1828. 

Urea does not occur in the vegetable world; it exists principally in 
the urine of man and of the mammalia; also in smaller quantity in the 
excrements of birds, fishes, and some reptiles; in the human and mam- 
malian blood, chyle, lymph, liver, spleen, lungs, brain, vitreous and aque- 
ous humors, saliva, perspiration, bile, milk, amniotic and allantoic fluids, 
muscular tissue, and in serous fluids (see below). 

Urea is formed in a number of reactions: 

First. — As a product of decomposition of uric acid in various ways. 

Second. — By the oxidation of oxamide. 

Third. — By the action of caustic potassa, and of other reagents upon 
creatin, sarcosine being formed at the same time: 

C^N.O, + H 2 = CON 2 H 4 + 3 H 7 NO S . 

Creatin. Water. Urea. Sarcosine. 

Fourth. — By the limited oxidation of albuminoid substances by potas- 
sium permanganate (see below). 

Fifth. — By the molecular transformation of its isomeride, ammonium 
cyanate: 

CN (CO) ) 

I = H 2 N, 

ONH 4 H 2 ) 

Ammonium cyanate. Urea. 

This is a step in the classical method of synthesis of Woehler, and of 
the process now used for the preparation of urea artificially. 

Sixth. — By the action of carbon oxychloride upon dry ammonia. 

Seventh. — By the action of ammonium hydrate on ethyl carbonate 
at 180°. 

Eighth. — By heating ammonium carbonate in sealed tubes to 130°. 

Ninth. — By the slow evaporation of an aqueous solution of hydro- 
cyanic acid. 

Preparation. — Urea is obtained either from the urine, or synthetically 
from ammonium cyanate. 

1. From the urine. — Fresh urine is evaporated to the consistency of a 
syrup over the water-bath; the residue is cooled and mixed with an 
equal volume of colorless nitric acid of sp. gr. 1.42; the crystals which 
separate are washed with a small quantity of cold water, and dissolved i:i 
hot water; the solution is decolorized, so far as possible, without boiling, 
with animal charcoal, filtered, and neutralized with potassium carbonate; 
17 



258 GENERAL MEDICAL CHEMISTRY. 

the liquid is then concentrated over the water-bath, and decanted from 
the crystals of potassium nitrate which separate; then evaporated to dry- 
ness over the water-bath, and the residue extracted with strong, hot alco- 
hol; the alcoholic solution, on evaporation, leaves the urea more or less 
colored by urinary pigment. 

2. By synthesis. — Urea is more readily obtained in a state of purity 
from potassium cyanate. This is dissolved in cold water, and dry ammo- 
nium sulphate is added to the solution. Potassium sulphate crystallizes 
out and is separated by decanting the liquid, which is then evaporated 
over the water-bath, fresh quantities of potassium sulphate crystallizing 
and being separated during the first part of the evaporation; the dry resi- 
due is extracted with strong, hot alcohol; this, on evaporation, leaves the 
urea, which, by a second crystallization from alcohol, is obtained pure. 

Urea crystallizes from its aqueous solution in long, flattened prisms, 
and by spontaneous evaporation of its alcoholic solution in quadratic prisms 
with octahedral ends. It is colorless and odorless; has a cooling, bitterish 
taste, resembling that o\ saltpetre; is neutral in reaction; soluble in one 
part of water at 15°, the solution being attended with diminution of tem- 
perature; soluble in five parts of cold alcohol (sp. gr. 0.816) and in one 
part of boiling alcohol; very sparingly soluble in ether. When its powder 
is mixed with that of certain salts, such as sodium sulphate, the water of 
crystallization of the salt separates, and the mass becomes soft or even 
liquid. When pure it is not deliquescent, but is slightly hygrometric, 
and when it is to be weighed it should be dried at 100° and cooled, in a 
dessicator. 

Decompositions. — When heated to 130°, urea fuses; at a few degrees 
above that temperature it boils, giving off ammonia and ammonium car- 
bonate, and leaves a residue of ammelide, C 6 H 9 N 9 3 . When heated to 
150° — 170°, it is decomposed, leaving a mixture of ammelide, cyanuric 
acid, and biuret: 

8CON 2 H 4 = 2C0 2 4- C 6 H 9 N 9 3 + 7NH 3 + H 2 

Urea. Carbon dioxide. Ammelide. Ammonia. Water. 

3CON 2 H 4 = C 3 3 N 3 H 3 + 3NH 3 

Urea. Cyanuric acid. Ammonia. 

8CON.H, = C a H 6 N s O, + NH 3 

Urea. Biuret. Ammonia. 

One of the tests for urea is based upon the formation of biuret. If 
maintained at 150° — 170° for some time, a dry, grayish mass remains, which 
consists principally of cyanuric acid. If, in this reaction, the volatile pro- 
ducts be condensed, they will be found to contain urea, not that that sub- 
stance is volatile, but because a portion of the cyanuric acid and ammonia 
have united to regenerate urea by the reverse action to that given above. 

Dilute aqueous solutions of urea are not decomposed by boiling; but 
if the solution be concentrated, or the boiling prolonged for a long time, 
the urea is partially decomposed into carbon dioxide and ammonia. The 
same decomposition takes place more rapidly and completely when a solu- 
tion of urea is heated under pressure to 140°. 

A pure aqueous solution of urea is not altered by exposure to filtered 
air. If urine be allowed to stand, putrefactive changes take place under 



CARBAMIDE UREA. 



259 



the influence of a peculiar organized ferment, or of a diastase-like body 
which is a constituent of normal urine. 

Chlorine decomposes urea with production of carbon dioxide, nitrogen, 
and hydrochloric acid. Solutions of the alkaline hypochlorites and hypo- 
bromites effect a similar decomposition in the presence of an excess of 
alkali, according to the equation: 



CON 2 H 4 + 

Urea. 



3C10Na = 


= co 2 


+ 


2H 2 


+ N 2 + 


3ClNa 


Sodium 
hypochlorite. 


Carbon 
dioxide. 




Water. 


Nitrogen. 


Sodium 
chloride. 



Upon this decomposition are based the quantitative processes of Knop, 
Hiifner, Yvon, Davy, Leconte, etc. 

Nitrous acid, or nitric acid charged with nitrous vapors, decomposes 
urea according to the equation: 



C0N 2 H 4 


+ 


N.O, = 


= CO, 


Urea. 




Nitrogen 


Carbon 






trioxide. 


dioxide. 



+ N 4 + 

Nitrogen. 



2H„0 (1) 

Water. 



or the equation: 
2CON 2 H 4 + 

Urea. 



N.O, 

Nitrogen 
trioxide. 



CO,(NH.), + N, + CO, (2) 



Ammonium 
carbonate. 



Nitrogen. 



Carbon, 
dioxide. 



If the mixture be made in the cold, of one molecule of nitrogen tri- 
oxide to two molecules of urea, the decomposition is that indicated by 
Equation 2. If, on the other hand, the trioxide be gradually added to the 
previously warmed urea solution in the same proportion, half the urea is 
decomposed while the remainder remains unaltered, and, upon the addi- 
tion of a further and sufficient quantity of the trioxide, all the urea is de- 
composed according to Equation 1. Upon this reaction are based the 
processes of Grehant, Boymond, Draper, etc. 

When heated with mineral acids or alkalies, urea is decomposed with 
formation of carbon dioxide and ammonia; if the decomposing agent be 
an acid, carbon dioxide is given off, and an ammoniacal salt remains; .if 
an alkali, a carbonate of the alkaline metal remains and carbon dioxide is 
given off. Upon this decomposition are based the processes of Heintz 
and Ragsky, Bunsen, etc. 

Compounds. — Urea forms definite compounds, not only with acids, but 
also with certain oxides and salts. Of the compounds which it forms 
with acids, the most important are those with nitric and oxalic acids. 

Urea nitrate, CON 2 H 4 ,HN0 3 , is formed as a white crystalline mass 
when a concentrated solution of urea is treated, in the cold, with nitric 
acid. It is much less soluble in water than is urea, especially in the 
presence of an excess of nitric acid. When heated to 140° it is decom- 
posed with evolution of large quantities of carbon dioxide and nitrogen 
monoxide. It decomposes the carbonates with liberation of urea. If a 
solution of urea nitrate be evaporated over the water-bath, it is decom- 
posed, bubbles of gas being given off beyond a certain degree of concen- 
tration, and large crystals of urea, covered with smaller ones of urea 
nitrate, separate. Zinc added to a solution of urea nitrate causes its de- 
composition with evolution of equal volumes of nitrogen and carbon di- 
oxide. 



260 GENERAL MEDICAL CHEMISTRY. 

TTrea oxalate, 2C0N 2 H 4 ,H 2 C 2 4 — separates as a fine, crystalline pow- 
der from mixed aqueous solutions of urea and oxalic acid of sufficient 
concentration. It is acid in taste and reaction, less soluble in cold water 
than the nitrate, and less soluble in the presence of an excess of oxalic 
acid that in pure water. Its solution may be evaporated at the temper- 
ature of the water-bath without suffering decomposition. 

Of the compounds of urea with oxides, the most interesting are those 
with mercuric oxide, three in number: 

a. CON 2 H 4 ,2HgO is formed by gradually adding mercuric oxide to 
a solution of urea heated to near its boiling-point; the filtered liquid, on 
standing twenty-four hours, deposits crystalline crusts of the above com- 
position. 

j3. C0N 2 H 4 ,3Hg0 is formed as a gelatinous precipitate when mercuric 
chloride solution is added to a solution of urea containing potassium hy- 
drate. 

y. CON 2 H 4 ,4HgO is formed as a white, amorphous precipitate when 
a dilute solution of mercuric nitrate is gradually added to a dilute alka- 
line solution of urea, and the excess of acid neutralized from time to 
time. A yellow tinge in the precipitate indicates the formation of mer- 
curic subnitrate after the urea has been all precipitated (see Liebig's 
process, below). 

Of the compounds of urea with salts, that with sodium chloride is the 
only one of importance: 

CON 2 H 4 ,NaCl,H 2 0. — It is obtained in prismatic crystals when solu- 
tions of equal molecules of urea and sodium chloride are evaporated to- 
gether. It is deliquescent and very soluble in water. Its solution, when 
mixed with solution of oxalic acid, only forms urea oxalate after long 
standing, or on evaporation. 

Physiology. — Urea is a constant constituent of normal mammalian 
blood and urine, and is the chief product of the oxidation of albuminoid 
substances which occur in the body; the bulk of the nitrogen assimilated 
from the food ultimately making its exit from the body in the form of 
urea in the urine. 

The determinations of the amount of urea in the blood and fluids 
other than the urine are, owing to imperfections in the processes of 
analysis, not as accurate as could be desired, the error being generally a 
minus one. As, however, the results of the same observer, using the 
same method, are comparable with each other, some of the more prom- 
inent are given in the following table: 



Quantity of Urea in Grams per 1,000 Parts in Animal Fluids 

other than urine. 

Normal blood — dog 0.36 Picard. 

Normal blood — dog 0.19 Wurtz. 

Normal blood— dog 0.11—0.58 Treskin. 

Normal blood— dog 0.24—0.53 Munk. 

Normal blood — dog .14 — .85 Pekelharing. 

Normal blood — dog .22 Poiseuille & Gobley. 

Normal blood — cow 0.22 Poiseuille & Gobley. 

Normal blood — cow 0.19 Wurtz. 

Normal blood — goat 0.17 Meissner & Shephard. 



CARBAMIDE UEEA. 



261 



Normal blood — human 0.2- 

Normal blood — human 0.16 

Normal blood — human 0.14- 

Normal blood — human placental. . . . 0.28- 

Norrnal blood — human foetal 0.27 

Blood of dog before nephrotomy. . . . 0.26- 
Blood of doo*, three hours after ne- 

CD? 

phrotomy . 45- 

Blood of dog, twenty-seven hours after 

nephrotomy , . . 2 . 06- 

Human blood in cholera 2.4 

Human blood in cholera 3.6 

Human blood in Bright's 15 . 

Lymph — dog 0.16 

Lymph — cow 0.19 

Chyle— cow 0.19 

Milk 0.13 

Saliva 0.35 

Bile 0.30 

Fluid of ascites . 15 

Perspiration .43 

Perspiration 0.38 

Perspiration 0.88 



-0 . 4 G amgee. 

Picard. 
-0.18 Gautier. 
-0.62 Picard. 

Picard. 
-0.88 Grehant. 

-0.93 Grehant. 

-2.76 Grehant. 
Voit. 
Chalvet. 

Bright & Babington. 
Wurtz. 
Wurtz. 
Wurtz. 
Picard. 
Picard. 
Picard. 
Picard. 
Favre. 
Funke. 
Picard. 



The quantity of urea contained in human urine under various circum- 
stances of health and disease has been the subject of a great number of 
investigations, and a determination of the amount voided in a given case 
is frequently of great importance to the phvsician, as indicating the 
amount of disassimilation of nitrogenous material occurring in the body 
at the time. Under normal conditions the quantity of urea voided in 
twenty-four hours is subject to considerable variations, as is shown in the 
subjoined table: 



Amount of Urea in Human Urine — Normal. 



Parts per 
1,000. 

TJrineofsp.gr. 1009.2 9.88 

Urine of sp.gr. 1011.6 1139 

Urine of sp. gr. 1019.0 18.58 

Urine of sp. gr. 1026.0 25.80 

Urine of sp. gr. 1027.7 29.70 

Urine of sp. gr. 1028.0 27.08 

Urine of sp. gr. 1029.0 31.77 

Urine of adult male (average) 30.0 

Urine of adult male (average) .... 

Urine of adult male (average) 25 — 32 

Urine of adult male (average) 

Urine of adult male (average) 23 3 

Urine of adult male, animal food 

Urine of adult male, mixed food 

Urine of adult male, vegetable food. 

Urine of adult male, non-nitrogenized food 

Urine of old men 84 — 86 years 

Urine of adult female (average) 



Grams in total 
urine of 24 
hours. 

Millon. 

Millon. 

Boymond. 

Millon. 

Millon. 

Boymond. 

Millon. 

Bcrzeliua. 

28.052 Lecanu. 
22—35 Neubauer. 
32—43 Kerner. 

35 Vogel. 

51—92 Franque. 

30—38 Franque. 

24 — 28 Franque. 

16 Franque. 

8.11 Lecanu. 
19.116 Lecanu. 



262 GENEKAL MEDICAL CHEMISTRY. 

Amount of Urea in Human Urine — Normal — Continued. 

Parts ner Grams in total 

T,ooo ™ of 24 

' hours. 

Urine of pregnant female 30 — 38 Quinquand. 

Urine of female, 24 hours after delivery 20 — 22 Quinquand. 

Urine of infant, first day 0.03 — 0.04 Quinquand. 

Urine of infant, fifth day 0. 12 — 0. 15 Quinquand. 

Urine of infant, eighth day ; . 0.2 — 0.28 Quinquand. 

Urine of infant, fifteenth day 0.3 — 0.04 Quinquand. 

Urine of child four years old 4 . 505 Lecanu. 

Urine of child eight years old .... 13 . 471 Lecanu. 

Urine of boy eighteen months old 8 — 12 Harley. 

Urine of girl eighteen months old 6 — 9 Harley. 

The variations are produced by: 

First. — Age. — In new-born children the elimination of urea is insig- 
nificant. By growing children the amount voided is absolutely less than 
that discharged by adults, but, relatively to their weight, considerably 
greater; thus, Harley gives the following amounts of urea in grams for 
each pound of body-weight in twenty-four hours: boy, eighteen months, 
0.4; girl, eighteen months, 0.35; man, twenty-seven years, 0.25; woman, 
twenty-seven years, 0.20. During adult life the mean elimination of urea 
remains stationary, unless modified by other causes than age. In old age 
the amount sinks to below the absolute quantity discharged by growing 
children. 

Second. — Sex. — At all periods of life females eliminate less urea than 
males. The proportion given by Beigel differs slightly from that of Har- 
ley, viz.: one kilo of male, 0.35 grams urea in twenty-four hours; one kilo 
of female, 0.25 grams. During pregnancy females discharge more urea 
than males; very shortly after delivery the amount sinks to the normal, 
below which it passes during lactation. 

Third. — Food. — The quantity of urea eliminated is in direct propor- 
tion to the amount of nitrogen contained in the food. The ingestion of 
large quantities of watery drinks increases the amount, and a contrary 
effect is produced by tea, coffee, and alcohol. With insufficient food the 
excretion of urea is diminished, although not arrested, even in extreme 
starvation. 

Fourth. — Exercise. — The question whether the elimination of urea is 
increased during violent muscular exercise is one which has been the sub- 
ject of many observations and of much discussion. An examination of 
the various results shows that, while the excretion of urea is slightly 
greater during violent exercise than during periods of rest, that increase 
is so insignificant in comparison to the work done, and, in some instances, 
to the loss of body-weight, as to render the assumption that muscular 
force is the result of the oxidation of the nitrosrenized constituents of 
muscle improbable. (See Gamgee: Physiological Chemistry, i., pp. 385 — 
401, for a full review of the subject.) 

The percentage of urea in the urine of the same individual is not the 
same at different times of the day. The minimum hourly elimination is 
in the morning hours; an increase begins immediately after the principal 
meal, and reaches its height in about six hours, when a diminution sets in 
and progresses to the time of the next meal. Gorup-Besanez gives a 
curve representing the hourly variations in the elimination of urea, which, 
reduced to figures, gives the following: 






CARBAMIDE UREA. 



263 





Urea 




Urea 




Urea 


Hour. 


in 


Hour. 


in 


Hour. 


in 




grains. 




grams. 




grams. 




1.5 


4- 5 P.M 


2.6 




1.9 


9-10 A.M 


1.5 


5- 6 p.m 


3.1 


1-2 A.M 


1.9 


10-11 A.M 


1.4 




2.8 


2-3 A.M 


1.9 


11 A.M. -12 M. .. 


1.3 


7- 8 p.m 


2 5 




1.8 


12M.-1 P.M 


1.8 


8- 9 p.m 


2.3 




1.6 


1-2 P.M 


1.9 


9-10 p.m 


2.0 




1.6 


2-3 p.m 


2.1 


10-11 P.M 


2.0 


6-7 A.M 


1.6 


3-4 p.m 


2.3 


11-12 P.M 


2.3 




1.5 



The total of which, however, represents a quantity above the normal. 

The absolute amount of urea eliminated in twenty-four hours is in- 
creased by the exhibition of diuretics, alkalies, colchicum, turpentine, 
rhubarb, alkaline silicates, and compounds of antimony, arsenic, and phos- 
phorus. It is diminished by digitalis, cafein, potassium iodide, and lead 
acetate; not sensibly affected by quinine. 

Pathologically the quantity of urea voided may be either increased or 
diminished: an increase above the normal indicating 1 an increased oxida- 
tion of nitrogenous material or the retention of the urea formed within 
the body; and a diminution a deficient oxidation of the same class of sub- 
stances, or, as is frequently the case, a diminution in the supply of nitro- 
gen to the body from loss of appetite or power of assimilation. 

In acute febrile diseases both the relative and absolute amounts of 
urea eliminated augments, with some oscillations, until the fever is at its 
height; there is, however, no constant relation between the amount of 
urea eliminated and the body temperature. During the period of defer- 
vescence, the amount of urea eliminated in twenty-four hours is diminished 
below the normal; during convalescence it again slowly increases. If the 
malady terminate in death the diminution of urea is continuous to the 
end. In intermittent fever the amount of urea discharged is increased on 
the day of the fever and diminished during the interval. In cholera, dur- 
ing the algid stage, the elimination of urea by the kidneys is almost com- 
pletely arrested, while the quantity in the blood is greatly increased. 
When the secretion of urine is a<rain established, the excretion of urea is 
greatly increased (sixty to eighty grams a day), and the abundant perspira- 
tion is also rich in urea. In cardiac diseases, attended with respiratory diffi- 
culty, but without albuminuria, the elimination of urea is diminished and 
that of uric acid increased. In nephritis, attended with albuminuria, the 
elimination of urea at first remains normal; later it diminishes, and the 
urea, accumulating in the blood, gives rise to urcemic poisoning . The 
quantity of urea in the urine is also diminished in all diseases attended 
with dropsical effusions; it is increased when the dropsical fluid is reab- 
sorbed. In true diabetes the amount of urea in the urine of twenty-four 
hours is greater than normal. In chronic diseases the elimination of urea 
is below the normal, owing to imperfect oxidation. 

Tests for urea. — To detect the presence of urea in a fluid, it is mixed 
with three to four volumes of alcohol, and filtered after having stood 
several hours in the cold; the filtrate is evaporated on the water-bath, and 
the residue extracted with strong alcohol; the filtered alcoholic fluid is 
evaporated, and the residue tested as follows: 

First. — A small portion is heated in a dry test-tube to about 100°, 



2G4 GENERAL MEDICAL CHEMISTRY. 

until the odor of ammonia is no longer observed; the residue is treated 
with a few drops of caustic potassa solution and three or four drops of 
cupric sulphate solution. If urea be present, the biuret resulting from 
its decomposition by heat (p. 258) causes the solution of the cupric oxide 
with a reddish violet color. 

Second. — A portion of the residue is dissolved in a drop or two of 
water and an equal quantity of colorless concentrated nitric acid added j^ 
if urea be present in sufficient quantity there appear white, shining, hex- 
agonal or rhombic crystalline plates or six-sided prisms of urea nitrate. 

Third. — A portion dissolved in water, as in second, is treated with a 
solution of oxalic acid; rhombic plates of urea oxalate crystallize. 

Determination of quantity of urea in urine. — It must not be forgotten 
that, in all quantitative determinations of constituents of the urine, the 
question to be solved is not how much of that constituent is contained in 
a given quantity of urine, but how much of that substance the patient is 
discharging in a given time, usually twenty-four hours. Quantitative 
determinations are, therefor, in most cases, barren of useful results, un- 
less the quantity of urine passed by the patient in twenty-tour hours is 
known; and, in view of diurnal variations in elimination, unless the 
urine examined be a sample taken from the mixed urine of twenty-four 
hours. 

There is no substance in the body for whose quantitative determina- 
tion so many processes have been suggested; yet, although some of these 
are sufficiently accurate for clinical purposes, there has been none hitherto 
devised, which, as applied to the urine, is free from sources of error. 

The processes giving the most accurate results are those of Bunsen 
and Draper, in both of which the urea is decomposed into carbon dioxide 
and ammonia, the former of which is weighed as barium carbonate. Un- 
fortunately, both processes require an expenditure of time and a degree 
of skill in manipulation, which render their application possible only in 
a well-appointed laboratory. 

A process which is described in all the text-books upon urinary analy- 
sis, and which is much used by physicians, is that of Liebig. As this 
method is one, however, which contains more sources of error than any 
other, and as it can only be made to yield approximately correct results 
by a very careful elimination, as far as possible, of those defects, it is not 
one which is adapted to the use of the physician. 

Probably the most satisfactory process in the hands of the practi- 
tioner is that of Hufner, based upon the reaction, to which attention was 
first called by Knop, of the alkaline hypobromites upon urea (p. 259); 
using, however, Dietrich's apparatus, or the more simple modification 
suggested by Rumpf, in place of that of Hiifner. The apparatus consists 
of a burette of 30 — 50 c.c. capacity, immersed in a reversed position in a 
glass cylinder, filled with water, and of such size that the burette can be 
completely immersed. The nozzle of the burette is connected with a piece 
of stout glass tubing about six inches long, bent at a right angle at about 
two inches from its upper end, and held by a support in such a way that 
the burette, which is to act as a gasometer, may be elevated or depressed 
at pleasure; the other end of the glass tubing is fitted to a piece of rub- 
ber tubing about three feet lonrr. The other end of the rubber tube is 
connected with a short piece of glass tubing, which passes through an 
opening in a rubber cork, which has another hole giving passage to a 
short piece of glass tube fitted with a rubber tube closed with a pinch- 
cock; the rubber cork is inserted into the mouth of a wide-mouthed flask 



CARBAMIDE UREA. 265 

of about 75 c.c. capacity; a short test-tube, of about 15 c.c. capacity, 
and of such size that it may be made to stand inside the bottle without 
spilling its contents; all joints must be air-tight. 

The reagent required is made as follows: 27 c.c. of a solution of 
caustic soda, made by dissolving one hundred grams NaHO in 250 c.c. 
H 2 0, are brought into a glass-stoppered bottle, 2.5 c.c. bromine are 
added, the mixture shaken, and diluted with water to 150 c.c. The caus- 
tic soda solution may be kept in a glass-stoppered bottle, whose stopper 
is well paraffined, but the mixture must be made up as required. 

To conduct a determination, about 20 c.c. of the hypobromite solution 
are placed in the decomposing-bottle; 5 c.c. of the urine to be examined 
are placed in the test-tube, which is then introduced into the bottle, care 
being taken that no urine escapes, the cork is then inserted, the pinch- 
cock opened and the burette adjusted in the cylinder so that the level of 
the water cuts the highest point in the graduation. The pinch-cock is 
now closed and the decomposing bottle inclined and shaken, so that the 
urine and hypobromite solution mix; the decomposition begins at once, 
and the evolved nitrogen passes into the burette, which is raised from 
time to time, so as to keep the external and internal levels of water about 
equal; the carbon dioxide formed is retained by the soda solution. In 
about an hour (the decomposition is usually complete in fifteen minutes, 
but it is well to wait an hour) the height is so adjusted that the inner 
and outer levels of water are exactly even and the graduation is read, 
while the standing of the barometer and thermometer are noted at the 
same time. 

In calculating the percentage of urea from the volume of nitrogen 
obtained, it is essential that a correction should be made for differences 
of temperature and pressure, without which the result from an ordinary 
sample of urine may be vitiated by an error of ten per cent. If, however, 
the temperature and barometric pressure have been noted, the correction 
is readily made by the use of the table on pages 266 and 267, computed 
by Dietrich. 

In the square of the table in which the horizontal line of the observed 
temperature crosses the vertical one of the observed barometric pressure 
will be found the correct weight, in milligrams, of a cubic centimetre of 
nitrogen; this, multiplied by the observed volume of nitrogen, gives the 
weight of nitrogen furnished by the urea. But as 60 parts of urea yield 
28 of nitrogen, the weight of nitrogen multiplied by 2.14 gives the weight 
of urea in milligrams contained in the 5 c.c. (or other quantity) of urine 
decomposed. This quantity, multiplied by twice the amount of urine 
passed in 24 hours, and divided by 1,000, gives the amount of urea 
eliminated in 24 hours in grams. 

Example. — 5 c.c. of urine decomposed; barometer = 742; thermom- 
eter=20; nitrogen collected = 14.5. 

From the table, the weight of 1 c.c. N at the above temperature and 

pressure is 1.116. 1.116 X 14.5 = 16.18 milligr. nitrogen collected; 16.18 x 

2.14=34.625 millicrr. urea in 6 c.c. urine. The patient passed in 24 hours 650 

1300x34.63 AKM , . . , 

c.c. urine, =45.02 ^rarns urea passed in 24 hours. 

1,0UU s r 

In using this process it is well to have the urea solution as near the 
strength of one per cent, as possible; therefor, if the urine be concentrated, 
as in the above example, it should be diluted. Even when carefully con- 
ducted, the process is not strictly accurate; creatinin and uric acid are 
also decomposed with liberation of nitrogen, thus causing a slight plus 



266 



GENERAL MEDICAL CHEMISTRY. 



Table of the Weight of One 







720 


722 


724 


726 


728 


730 


732 


734 


736 


738 


740 


742 


744 




rlO° 
11° 


1.13:38 


1.1370 


1.1402 


1.1434 


1.1466 


1.1498 


1.1529 


1.1561 


1.1593 


1.1625 


1.1657 


1.1689 


1.1721 




1.1288 


1.1320 


1.1352 


1.1384 


1.1415 


1.1447 


1 1479! 1.1511 


1.1542 


1.1574 


1.1606 


1.1638 


1.1H70 


"C 


12" 


1.1237 


1 .1269 


1.1301 


1.1333 


1.1364 


1.1396 


1.1428; 1.1459 1.1491 


1.1523 


1 J 554 


1.1586 


1.1618 


u 


13° 


1.1187 


1.1219 


1.1251 


1 . 1282 


1.1314 


1.1345 


1.1377 1.1409 1.1440 


1.1472 


1.1503 


1.1535 


1.1566 




l 4 o 


1.1136 1.1168 


1.1200 


1.1231 


1.1263 


1.1294 


1.1326 '1.1357 1.1389 


1.1420 


1.1452 


1.1483 


1.1515 


s 


15o 


1.1085 1.1117 


1.1149 


1.1180 


1.1211 


1.1243 


1.1274 j 1.1305 1.1337 


1.1368 


1.1399 


1.1431 


1.1462 


o 


16° 


1.1034 1.1068 


1.1007 


1.1128 


1.1160 1.1191 


1.1222; 1.1253 1.1285 


1.1316 


1.1347 


1 . 1378 


1.1409 




17° 


1.098311.1014 


1.1045 


1.1076 


1.1107 1.1138 


1.117011 1201 


1.1232 


1.1263 


1.1294 


1.1325 


1.1356 


lb" 


1.0930 1.0961 


1.0992 


1.1023 


1.1054 1.1085 


1.1117 1.1148 


1.1179 


1.1209 


1.1241 


1.1272 


1.1303 


>- 


19° 


1.0877;i.0;)08 


1.0939 


1.0970 


l.lOOi; 1.1032 


1. 1063 1.1094 1.1125 


1.1156 


1.1187 


1.1218 


1.1248 




20° 


1.0825,1.0855 


1.08S6 


1.0917 


1.0948 1.0979 


1.1009! 1.1040 1.1071 


1.1102 


1.1133 


1.1164 


1.1194 


a 


21° 


1.0771 


1.0802 1.0832 


1.0S63 


1.0894 1.0924 1.0955 


1.0986 


1.1017 


1.1047 


1.1078 1.1109 


1.1139 


S 


22° 


1.0717 


1.0.47 


1.0778 


1.0808 


1.0839 1.0870 j 1.0900 


1.0931 


1.0961 


1.0992 


1.1 0-23| 1.1053 


1.1084 


23° 


1.0662 


1.0692 


1.0723 


1.0753 


1.07S4 


1.081411.0845 


1.0875 


1.09G6 1.0936 


1.0967 1.0997 


1.1028 


H 


24° 


1.06 '6 


I.O606 


1.0667 


1.0697 


1 .0728 


1.0758 1.0789 


1.0819 


1.0849 1.08S0 


1.0910 


1.0940 


1.0971 




^25° 


1 .0550 


1.0580 


1.0610 


1.0641 


1.0671 


1 .0701 


1.0732 


1.0762 


1.0792 


1.0823 


1.0853 


1.0883 


1.0913 




720 


722 


724 


726 


728 


730 


732 


734 


736 


738 


740 


742 


744 



Barometric pressure in millimetres. 

error; on the other hand, a minus error is caused by the fact, that in the 
decomposition of urea by the hypobromite, the theoretical result is never 
obtained within about eight per cent, in urine. These errors may be 
rectified to a great extent by multiplying the result by 1.044. 

A process which does not yield as accurate results as the preceding, 
but which is much more easy of application, is that of Fowler, based upon 
the loss of specific gravity of the urine after the decomposition of its 
urea by hypochlorite. To apply this method the specific gravity of the 
urine is carefully determined, as well as that of the liq. sodae chlorinatse 
(Squibb's). One volume of the urine is then mixed with exactly seven 
volumes of the liq. sod. chlor., and, after the first violence of the reaction 
has subsided, the mixture is shaken from time to time during an hour, 
when the decomposition is complete; the specific gravity of the mixture 
is then determined. As the reaction begins instantaneously when the 
urine and reagent are mixed, the specific gravity of the mixture must be 
calculated by adding together once the specific gravity of the urine and 
seven times the specific gravity of the liq. sod. chlor., and dividing the 
sum by eight. From the quotient so obtained the specific gravity of the 
mixture after decomposition is subtracted; every degree of loss in spe- 
cific gravity indicates 0.7791 gram of urea in 100 c.c. of urine. The 
specific gravity determinations must all be made at the same tempera- 
ture; and that of the mixture only when the evolution of gas has ceased 
entirely. 

Finally, when it is only desired to determine whether the urea is 
greatly in excess or much below the normal, advantage may be taken of 
the formation of crystals of urea nitrate. Two samples of the urine are 
taken, one of 5 c.c. and one of 10 c.c; the latter is evaporated, at alow 
temperature, to the bulk of the former and cooled; to both one-third 
volume of colorless nitric acid is added. If crystals do not form within a 
few moments in the concentrated sample, the quantity of urea is below 
the normal; if they do in the unconcentrated sample, it is in excess. In 
using this very rough method, regard must be had to the quantity of 



COMPOUND UREAS. 



267 



Cubic Centimetre of Nitrogen. 



746 


748 


750 


752 


754 


756 


758 


760 


762 


764 


766 


768 


770 






1.1753 


1.1785 


1.1817 


1.1848 


1.1880 


1.1912 


1.1944 


1.1976 


1.2008 


1.2040 


1.2072 


1.2104 


1.2136 


10<n 
11° 




1.1701 


1.17:33 


1.1765 


1.1717 


1.1829 


1 . 1860 


1.1892 


1.1924 


1.1956 


1.1988 


1 2019 


1.2051 


1.2083 


i-3 


1.1649 


1.1681 


1.1713 


1.1744 


1.1776 


1.1808 


1.1839 


1.1871 


1.1903 


1.1934 


1.1966 


1.1998 


1.2029 


12° 


1.159S 


1.1630 


1.1661 


1.1693 


1.172-4 


1.1756 


1.1787 


1.1819 


1.1851 


1.1882 


1.1914 


1.1945 


1.1977 


13° 


y 


1.1546 


1.1577 


1.1609 


1.1640 


1.1672 


1.1703 


1.1735 


1.1766 


1.1798 


1.1829 


1.1861 


1.1892 


1.1923 


14o 


to 


1.1493 


1.1525 


1.1556 


1.1587 


1.1619 


1.1650 


1.1681 


1.1713 


1.1744 


1 .1775 


1.1807 


1.1838 


1.1869 


15° 


p 


1.1441 


1.1472 


1.1503 


1.1534 


1.1566 


1.1597 


1.1628 


1.1659 


1.1691 


1 .1722 


1.1753 


1.1784 


1.1816 


16° 


C 


1 1397 


1.1419 


1.1450 


1.1481 


1.1512 


1.1543 


1.1574 


1.1605 


1.1636 


1.1667 


1.1699 


1 .1730 


1.1761 


17° 


CD 


1.1334 


1.136.=) 


1.1396 


1.1427 


1.1458 


1.1489 


1.1520 


1.1551 


1.1582 


1.1613 


1.1644 


1.1675 


1.1706 


18" 


" 3 


1.1279 


1.1310 


1.1341 


1.1372 


1.1403 


1.1434 


1.1465 


1.1496 


1 .1527 


1.1558 


1.1539 


1.1620 


1.1650 


19° 


Q 


1.1225 


1.12.6 


1.1287 


1.1318 


1.1348 


1.1379 


1.1410 


1.1441 


1.1472 


1.1502 


1.1533 


1.1564 


1.1595: 


20° 


3 


11.1170 


1.1201 


1.1231 


1.1262 


1.1293 


1.1324 


1.1354 


1.1385 


1.1416 


1.1446 


1 .1477 


1.1508 


1 .1539 


21° 


ct- 

P 


11.1115 


1.1145 


1.1176 


1.1206 


1.1237 


1.126S 


1.1298 


1.1329 


1.1359 


1.1390 


1.1421 


1.1451 


1.1482 


22° 


1.1058 


1.108!) 


1.1119 


1.1150 


1.1180 


1.1211 


1.1241 


1.1272 


1.1302 


1.1333 


1.1363 


1.1394 


1.1424 


23° 


1.1001 


1.1032 


1.1062 


1.1092 


1.1123 


1.1153 


1.1184 


1.1214 


1.1244 


1.1275 


1.1305 


1.1336 


1.1366 


24° 




1.0944 


1.0974 


1.1004 


1.1035 


1.1065 


1.1095 


1.1126 


1.1156 


1.11S6 


1.1216 


1.1247 


1.1277 


1.1307 


25° J 


I 


746 


748 


750 


752 


754 


756 


758 


760 


762 


764 


766 


768 


770 







Barometric pressure in millimetres. 



urine passed in twenty-four hours; the above applies to the normal 
amount of 1,200 c.c. ; if the quantity be greater or less, the urine must 
be concentrated or diluted in proportion. 

Obviously this process cannot be used when the urine is albuminous. 



Sulphurea, CS^^*, 

is a compound bearing the same relation to urea that carbon disul- 
phide bears to carbon dioxide, and may be obtained from ammonium sul- 
phocyanate as urea is obtained from ammonium cyanate. It forms large 
prismatic crystals or long needles, very soluble in water and alcohol, dif- 
ficultly soluble in ether. It forms salts and other compounds, similar to 
those of urea in constitution. 



Compound Ureas. 

These compounds, which are exceedingly numerous, may be considered 
as formed by the substitution of one or more alcoholic or acid radicals 
for one or more of the remaining hydrogen atoms of urea. 

Those containing alcoholic radicals may be obtained, as urea is ob- 
tained from ammonium cyanate, from the cyanate of the corresponding 
compound ammonium; or by the action of ammonia, or of the compound 
ammonias, upon the cyanic ethers. 

Those containing acid radicals have received the distinctive name of 
ureids; some of them are of great interest as derivatives of uric acid, 
which is itself probably an ureid. We will limit our consideration of 
these bodies to uric acid and the ureids obtained from and related to it. 



268 GENERAL MEDICAL CHEMISTRY. 



Urio Acid— Lithic Acid— OET N O q . 

D 4 4 3 

Constitution unknown. So far as yet known, uric acid is exclusively 
an animal product. It exists in the urine of man and of the carnivora, 
and in that of the herbivora when, during early life or starvation, they 
are for the time being carnivora; as a constituent of urinary calculi; and 
very abundantly in the excrement of serpents, tortoises, birds, molluscs, 
and insects, also in guano. It is present in very small quantity in the 
blood of man, more abundantly in that of gouty patients and in that of 
birds; the so-called "chalk-stones" deposited in the joints of gouty pa- 
tients are composed of sodium urate. It also occurs in the spleen, lungs, 
liver, pancreas, brain, and muscular fluid. 

Although uric acid may be obtained from calculi, urine, and guano, 
the source from which it is most readily obtained in a state of purity is 
the solid urine of large serpents, which is composed almost entirely of 
uric acid and the acid urates of sodium, potassium, and ammonium. This 
is dried, powdered, and dissolved in a solution of potassium hydrate, con- 
taining one part of potash to twenty of water; the solution is boiled 
until all odor of ammonia has disappeared. Through the filtered solution 
a current of carbon dioxide is passed, through a wide tube, until the pre- 
cipitate, which was at first gelatinous, has became granular and sinks to 
the bottom; the acid potassium urate so formed is collected on a filter, 
and washed with cold water until the wash-water becomes turbid when 
added to the first filtrate; the deposit is. now dissolved in hot dilute 
caustic potassa solution, and the solution filtered hot into hydrochloric 
acid diluted with an equal volume of water. The precipitated uric acid 
is washed and dried. 

Uric acid, when pure, crystallizes in small, white, rhombic, rectangular 
or hexagonal plates, or in rectangular prisms, or in dendritic crystals of a 
hydrate, C.H 4 N 4 3 ,2H 2 0. As crystallized from urine it is more or less 
colored with urinary pigments, and forms rectangular or rhombic plates, 
usually with the angles rounded so as to form lozenges, which are ar- 
ranged in bundles, daggers, crosses, or dendritic groups, sometimes of 
considerable size. It is almost insoluble in water, requiring for its solu- 
tion nineteen hundred parts of boiling water and fifteen thousand parts 
of cold water; insoluble in alcohol and ether; its aqueous solution is acid 
to test-paper; cold hydrochloric acid dissolves it more readily than water, 
and on evaporation deposits it in rectangular plates. It is tasteless and 
odorless. 

When heated, uric acid neither fuses nor sublimes, but is decomposed 
with formation of hydrocyanic and cyanuric acids, urea and ammonium 
cyanate. When heated in a current of chlorine, it yields cyanuric and 
hydrochloric acids; when a current of chlorine is passed for some time 
through water holding uric acid in suspension, alloxan, parabanic and 
oxalic acids, and ammonium cyanate are formed; similar decompositions 
are produced by bromine and iodine. Hydrochloric acid simply dissolves 
it. Sulphuric acid dissolves it; a hot solution deposits a deliquescent 
crystalline compound, C 5 H 4 N 4 O s ,4S0 4 H 2 ; when heated with sulphuric 
acid to 140° for some time, it is partly decomposed with formation of hy- 
durilic acid and pseudoxanthine. Ozone oxidizes uric acid with forma- 
tion of allantoin, carbon dioxide, and urea. The action of nitric acid 
varies with the temperature; it dissolves in cold nitric acid with effer- 
vescence and formation of alloxan, alloxantine, and urea, which last is 



COMPOUND UREAS. 269 

itself decomposed by the excess of nitric acid. On heating the mixture, 
or by oxidation of uric acid with hot nitric acid, the alloxan and alloxan- 
tine formed are converted into parabanic acid. A solution of uric acid 
in nitric acid, treated with ammonium hydrate and slightly heated, turns 
purple from the formation of murexid or ammonium pur pur ate (see p. 270). 
Solutions of the alkalies dissolve uric acid with formation of neutral 
urates. Uric acid is bibasic. forming two series of salts with the alkaline 
metals. 

It is more convenient to consider the urates in this place than under 
their respective metallic elements. 

Ammonium urates. — The neutral salt, C 5 H 2 N 4 3 (NH 4 ) 2 is unknown. 
The acid salt, C 5 TI 3 N 4 3 (NIT 4 ), exists as a constituent of the urine of 
the lower animals, and occurs, accompanying other urates and free uric 
acid, in urinary sediments and calculi. Sediments of this salt are rust- 
yellow or pink in color, amorphous, or composed of globular masses, set 
with projecting points, or elongated dumb-bells, and are formed in alkaline 
urine. It is very sparingly soluble in water; soluble in warm hydrochloric 
acid, from which solution crystalline plates of uric acid are deposited. 

Potassium urates. — The neutral salt, C 5 H 2 N 4 3 K 2 , is obtained when a 
solution of potassium hydrate, free from carbonate, is saturated with uric 
acid; the solution on concentration deposits the salt in fine needles. It 
is soluble in forty-four parts of cold water and in thirty-five parts of 
boiling water. It is alkaline in taste, and absorbs carbon dioxide from 
the air. 

The acid salt, C 6 H 3 N 4 3 K, is formed as a granular (at first gelatinous) 
precipitate when a solution of the neutral salt is treated with carbon 
dioxide. It dissolves in eight hundred parts of cold water and in eighty 
parts of boiling water. The occurrence of potassium urates in urinary 
sediments and calculi is very exceptional. 

Sodium urates. — The neutral salt, C & H 2 N 4 3 Na 2 , is formed under 
similar conditions as the corresponding potassium salt. It forms nodular 
masses, soluble in seventy-seven parts of cold water and in seventy-five 
of boiling water ; it absorbs carbon dioxide from the air. 

The acid salt, C t H Q N\0 Q Na, is formed when the neutral salt is treated 
with carbon dioxide. It is soluble in twelve hundred parts of cold 
water and in one hundred and twenty-five parts of boiling water. It 
occurs in urinary sediments and calculi, very rarely crystallized. The 
arthritic calculi of gouty patients are almost exclusively composed of this 
salt, frequently beautifully crystallized. 

Calcium urates. — The neutral salt, C 6 H 2 N 4 3 Ca, is obtained by drop- 
ping a solution of neutral potassium urate into a boiling solution of cal- 
cium chloride until the precipitate is no longer redissolved, and then 
boiling for an hour. A granular powder, soluble in fifteen hundred 
parts of cold water and in fourteen hundred and forty parts of boiling 
water. 

The acid salt, (C B H 3 N 4 3 ) 2 Ca, is obtained by decomposing a boiling 
solution of acid potassium urate with calcium chloride solution. It 
crystallizes in needles, soluble in six hundred and three parts of cold 
water and in two hundred and seventy-six parts of boiling water. It 
occurs occasionally in urinary sediments and calculi, and in " chalk 
stones." 

Lithium urates. — The acid salt, C B H 3 N 4 3 Li, is formed by dissolving 
uric acid in a warm solution of lithium carbonate. It crystallizes in 
needles, which dissolve in sixty parts of water at 50°, and do not separate 



270 GENERAL MEDICAL CHEMISTRY. 

when the solution is cooled. It is with a view to the formation of this, 
the most soluble of the urates, that the compounds of lithium are given 
to patients suffering with the uric acid diathesis. 

Physiology. — Uric acid exists in the economy chiefly in combination 
as its sodium salts ; it is occasionally found free, and from the probable 
method of its formation it is difficult to understand how all the uric acid 
in the economy should not have existed there free, at least at the 
instant of its formation. It can scarcely be doubted, although there is 
no experimental proof in support of this view, that uric acid is one of 
the products of the oxidation of the albuminoid substances — an oxidation 
intermediate in the production of urea ; and that consequently diseases 
in which there is an excessive formation of uric acid, such as gout, have 
their origin in defective oxidation. 

In human urine the quantity of uric acid varies with the nature of 
the food in the same manner as does urea, and about in the same pro- 
portion: 

Urea. Uric acid. JS^S^L 

uric acid to urea. 

Animal food 71.5 1.25 57.2 

Mixed food 37.0 0.76 48.7 

Vegetable food 26.0 0.50 52.0 

Non-nitrogenized food 16.0 0.34 47.0 

The mean elimination of uric acid in the urine is from one-thirty-fifth to 
one-sixtieth of that of urea, or about 0.5 to 1.0 gram in twenty-four 
hours. With a strictly vegetable diet the elimination in 24 hours may 
fall to 0.3 grains, and with a surfeit of animal food it may rise to 1.5 
grams. The hourly elimination is increased after meals, and diminished 
by fasting and by muscular and mental activity. 

Deposits of free uric acid occur in acid, concentrated urines. In gout 
the proportion of uric acid in the urine is diminished, although, owing to 
the small quantity of urine passed, it may be relatively great; during the 
paroxysms the quantity of uric acid is increased both relatively and 
absolutely. The proportion of uric acid in the blood is invariably in- 
creased in gout. 

Tests. — Uric acid may be recognized by its crystalline form and by 
the murexid test. To apply this test the substance is moistened with 
nitric acid, which is evaporated nearly to dryness at a low temperature; 
the cooled residue is then moistened with ammonium hydrate. If uric 
acid be present, a yellow residue — sometimes pink or red when the uric 
acid was abundant — remains after the evaporation of the nitric acid, and 
this, on the addition of the alkali, assumes a rich purplish red color. 

To detect uric acid in the blood, about two drachms of the serum are 
placed in a flat glass dish and faintly acidulated with acetic acid ; a very 
fine fibril of linen thread is placed in the liquid, which is set aside and 
allowed to evaporate to the consistency of a jelly ; the fibril is then 
removed and examined microscopically. If the blood contain uric acid 
in abnormal proportion, the thread will have attached to it crystals of 
uric acid. 

Quantitative determination. — The best method for the determination 
of the quantity of uric acid in urine is the following : 250 c.c. of the fil- 
tered urine are acidulated with 10 c.c. of hydrochloric acid, and the mix- 
ture set aside for twenty-fours in a cool place. A small filter is washed, 
first with dilute hydrochloric acid and then with water, dried at 100°, and 
weighed. At the end of the twenty-four hours this filter is moistened in 



UREIDS DERIVED FROM URIC ACID. 



271 



a funnel, and the crystals of uric acid collected upon it (those which 
adhere to the walls of the precipitating vessel are best separated by a 
small section of rubber tubing passed over the end of a glass rod, and 
used as a brush). No water is to be used in this part of the process, the 
filtered urine being passed through a second time, if this be required, to 
bring all the crystals upon the filter. The deposit on the filter is now 
washed with 35 c.c. of pure water, added in small portions at a time; the 
filter and its contents are then dried and weighed. The difference be- 
tween this weight and that of the filter alone is the weight of uric acid 
in 250 c.c. of urine. If from any cause more than 35 c.c. of wash-water 
have been used, mgr '. 043 must be added to this weight for every c.c. 
of extra wash-water. 

If the urine contain albumen, this must first be separated by adding 
two or three drops of acetic acid, heating to near 100°, until the coagulum 
becomes flocculent, and filtering. 



Ureids derived from Uric Aeid. 

These substances are quite numerous, and are divisible into ureids, 
diureids, triureids, and uramic acids, according as they are formed by sub- 
stitution in one, two, or three molecules of urea, and according as the 
acid radical substituted does or does not retain a group COOH. The 
more prominent may be arranged in two parallel groups, the correspond- 
ing terms of which differ from each other by CO, thus : 



C 8 H,N,0, 

Oxalylurea 
(parabanic acid). 



Ureids. 
Parabanic series. 



Glyoxylurea 
(allanturic acid). 



O.H 4 N,o. 

Glycolylnrea 
(hydantoin). 



C.H.N.O, 

Mesoxalylurea 
(alloxan). 



Alloxanic series. 

Tartryonyl urea 
(dialyuric acid). 



C.H.N.O. 

Malonylurea 
(barbituric acid). 



Glyoxyldiurea 
(allantoin). 



Diureids. 



C 6 H 4 N 4 5 

Oxalyl-glyoxyldiurea 
(oxalantine). 



C 5 H 6 N 4 0, 

Tartronyldiurea 
(pseudo-uric acid). 



C 8 H 4 N 4 0, 

Mesoxalyl-tartronyldiurea 
(alloxantine). 



C s H.N,0, 

Hydantoic acid. 



Uramic Acids. 

Oxaluric acid. 



C.H,N,0, 

Alloxanic acid. 



Some of these substances require a brief mention : 

Oxalylurea, or parabanic acid, is urea in which two atoms of hydro- 
gen have been replaced by the divalent radical (C 2 2 )" of oxalic acid. 
It is obtained by the oxidation of uric acid, or of alloxan by hot nitric 
acid. It forms six-sided transparent prisms, acid in taste, and very soluble 
in water and alcohol. 



272 GENEKAL MEDICAL CHEMISTRY. 

Glyoxyldiurea, or allantoin, is, as its more common name implies, ob- 
tained from the allantoic fluid of the cow; it has also been found to 
exist in the urine of sucking calves, in that of dogs and cats when fed 
upon meat, in that of children during the first eight days of life, in that 
of adults after the ingestion of tannin, and in that of pregnant women. 

It may be obtained artificially by oxidizing uric acid held in suspen- 
sion in boiling water, with pure oxide of lead. 

It crystallizes in small, odorless, tasteless, colorless, neutral and trans- 
parent prisms; sparingly soluble in cold water, readily in warm water, 
alcohol, and ether. When heated with alkalies it yields oxalic acid and 
ammonia; with dilute acids, allanturic acid/ and with oxidizing agents, 
urea and allantoic acid. 

It is probably, like uric acid, an intermediate product of the oxidation 
of the albuminoids. 

Mesoxalylurea, or alloxan, is a product of the limited oxidation of uric 
acid. It has been found in one instance in the intestinal mucus, in a case 
of diarrhoea, and probably in the urine in a case of heart disease. 

It forms colorless crystals, readily soluble in water. When exposed 
to the air it gradually turns red, which color it communicates to the skin 
on contact with it. 

Oxaluric acid occurs, as its ammonium salt, as a normal constituent, 
in small but constant quantity, of human urine, from which it can only 
be obtained by operating upon large quantities. It may also be obtained 
by heating parabanic acid with calcium carbonate. 

It forms a white, sparingly soluble powder, which, on boiling with 
water or with the alkalies, is converted into urea and oxalic acid. The 
ammonium salt crystallizes in white, glistening needles, sparingly soluble 
in water. 

Its ready conversion into urea and oxalic acid, and its formation from 
parabanic acid, itself a product of oxidation of uric acid, shows it to be 
one of the numerous terms in the oxidation of the nitrogenous constitu- 
ents of the body. 



Substances of Unknown Constitution Related to Uric Acid. 

There exist several substances, of unknown constitution, which, from 
their products of decomposition and their occurrence, seem to be closely 
related to uric acid; some of these occur in the animal economy: xanthine, 
hypoxanthine, guanine, carnine. 



Xanthine, C 6 H 4 N 4 O a . 

Sometimes called xanthic oxide or urous acid, was first discovered as 
a constituent of a rare form of urinary calculus; since that time it has 
been found to exist in small quantity in the pancreas, spleen, liver, thy- 
mus and brain of mammals and fishes; also in human urine after the use of 
sulphur baths and inunctions. 

When dry it forms an amorphous, yellowish white powder; very spar- 
ingly soluble in cold water, rather more freely in hot water. If dissolved 
in nitric acid and the solution evaporated by heat, xanthine leaves a yel- 
low residue, which assumes a reddish yellow color on contact with potas- 
sium hydrate solution, and this when heated turns violet-red. 



CAEKTNE. 273 

Xanthine calculi are of very infrequent occurrence; they vary in size 
from that of a pea to that of a pigeon's egg; are rather hard, brownish 
yellow, smooth, shining, and made up of well-defined, concentric layers; 
their broken surface assumes a waxy polish when rubbed. 



Hypoxanthine — Sarcine — C 5 H 4 N 4 0, 

was discovered in the spleen; it has also been found to exist in the 
muscular tissue of mammals, in the thymus, suprarenal capsules, and 
brain; in the human liver in acute yellow atrophy; and in the blood and 
urine, accompanied by xanthine, in leucocythaemia; and probaby in small 
quantity in healthy blood; and in the marrow of bones. 

It is best obtained from the mother-liquor of the preparation of crea- 
tine (q. v.); this is diluted with water, rendered alkaline with ammonium 
hydrate, and treated with silver nitrate in ammonical solution; the pre- 
cipitate is washed with dilute ammonia by decantation, collected on a filter, 
and extracted with boiling nitric acid; sp. gr. 1.1; the nitric acid solution, 
on cooling, deposits a compound of silver nitrate and hypoxanthine; this is 
suspended in water, decomposed by hydrogen sulphide; the filtered solu- 
tion on concentration deposits crystals of hypoxanthine nitrate. 

Free hypoxanthine, obtained from the nitrate by decomposition with 
ammonium hydrate, forms nodular masses, never crystals; soluble in 
three hundred parts cold and seventy-eight parts boiling water, sparingly 
soluble in alcohol, readily in dilute acids and alkalies, with which and 
with metallic salts it forms compounds. It may be obtained from uric 
acid or xanthine by the action of sodium amalgam, and when oxidized 
with nitric acid it yields xanthine. The close relationship of these bodies 
is shown by the. formulae: 



Uric acid C 5 H 4 N 4 

Xanthine C 5 H 4 N 4 

Hypoxanthine C 5 H 4 N 4 Q 



2 



The flesh of the ox contains 0.022 per cent, of hypoxanthine; that of 
the rabbit 0.026 per cent.; leucocythsemic blood 0.0075 per cent. 

Guanine, C 6 H 6 N 6 0, 

as its name implies, was first obtained from guano; it has also been 
found in the pancreas, lungs and liver of certain mammalians, and in the 
excrements of the lower orders. 

It appears as a white or yellowish amorphous mass; odorless and 
tasteless; almost insoluble in water, alcohol and ether; readily in acids 
and alkalies, with which it forms compounds. 



Carnine, C 7 H 8 N 4 3 + H a O, 

has been obtained from Liebig's meat extract. It forms chalky, micro- 
scopic crystals; sparingly soluble in cold, readily in warm water; insoluble 
in alcohol and ether. Forms compounds with acids and alkalies similar 
to those of hypoxanthine. 
18 



274 GENERAL MEDICAL CHEMISTRY. 



COOH 

Carbamic Acid, , 

NH 2 

has not been isolated, and is only known in combination as its ammonium 
salt and in its ethers; the latter are known under the generic name of 
■ur ethanes. Its ammonium salt exists in sesquicarbonate of ammonium 
(q. v.), and has been said to exist in blood-serum (see p. 256). 

The remaining acids of this series, being monobasic, each forms a 
single amide. None of these amides are of other than theoretic interest. 



Amides of the Acid Series, C n H 2n _ 2 4 . 
CO-NH 



"2 



Oxamide, , was one of the first of this class of substances 

CO-NH, 
obtained. It is formed by depriving ammonium oxalate of the elements 
of two molecules of water, or by the action of ammonia upon ethyl oxa- 
late. 

It forms a light, white, crystalline powder; odorless, tasteless, and 
neutral; almost insoluble in cold water, sparingly soluble in warm water. 
It is decomposed by sulphuric acid into the two oxides of carbon and 
ammonium sulphate; by phosphoric anhydride into water and cyanogen; 
by mercuric oxide into urea and carbon dioxide; and by acids and alka- 
lies into oxalic acid and ammonia. 

Corresponding to it there exist a number of substances constituted by 
the substitution of alcoholic radicals for the remaining hydrogen atoms, 
and consequently comparable to the ureids. 
CO-NH 2 

Oxamic acid, | , is formed by the dry distillation of ammo- 

CO,OH 
nium oxalate at 220° — 230°. It appears as a fine, colorless powder; spar- 
ingly soluble in water and alcohol; insoluble in ether; fusible at 173°. 

The remaining acids of this series are capable of forming compounds 
similar to the above, none of which, however, require further notice. 



TRIATOMIC ALCOHOLS. 

There is as yet only one alcohol known containing a trivalent radical. 
This is glycerin, whose relation to the monoatomic and diatomic alcohols 
is shown by the following formulae: 

Propane. Propyl alcohol. Propyl glycol. Glycerin. 

CH. CH. CH OH CH OH 



CH CH, CH 3 CHOH 

I I 1 I 

CH; CH 3 OH CH a OH CH a OH 



GLYCERIN. 



275 



Glycerin, CH 5 (OH) 3 , 

was first obtained as a secondary product in the manufacture of lead 
plaster; it is now produced as a by-product in the manufacture of soaps 
and of stearin candles. It exists free in palm-oil and in other vegetable 
oils; it is produced in small quantity during alcoholic fermentation, and 
is consequently present in wine and beer. It is much more widely dis- 
seminated in its ethers, the neutral fats, in the animal and vegetable 
king-doms. 

It has been obtained by partial synthesis, by heating for some time a 
mixture of allyl tribromide, silver acetate and acetic acid, and saponify- 
ing- the triacetin so obtained. 

The glycerin obtained by the process now generally followed — the 
decomposition of the neutral fats and distillation of the products in a 
current of superheated steam — is free from the impurities which contami- 
nated the products of the older processes. The only impurity likely to be 
present is water, which may be recognized by the low specific gravity of 
the mixture. 

Glycerin is a colorless, odorless, syrupy liquid; has a sweetish taste; 
sp. gr. 1.26 at 15°. Although it cannot usually be caused to crystallize 
by the application of the most intense cold, it does so sometimes under 
imperfectly understood conditions, forming small white needles of sp. gr. 
1.268, and fusible between 7° and 8°; it is soluble in all proportions in 
water and alcohol, insoluble in ether and in chloroform. The specific 
gravity of mixtures of glycerin and water are: 



Per cent, 
glycerin. 


Specific gravity. 


Per cent, 
glycerin. 


Specific gravity. 


Per cent, 
glycerin. 


Specific gravity. 


10 
20 
30 


1.024 
1.051 
1.075 


40 
50 
60 


1.105 
1.127 
1.159 


70 
80 
90 


1.170 
1.220 
1.232 



Glycerin is a solvent of a great number of mineral and organic sub- 



stances; 100 parts of glycerin dissolve: 



Parts. 

Sodium carbonate. . . . 98.0 

Borax 60.0 

Tannin... 50.0 

Urea 50.0 

Potassium arsenate ... 50.0 

Sodium arsenate 50.0 

Zinc chloride 50.0 

Potassium iodide 40.0 

Zinc iodide 40.0 

Alum 40.0 

Zinc sulphate 35.0 

Atropine sulphate 33.0 

Potassium cyanide .... 32. 

Cupric sulphate 30.0 

Mercuric cyanide 27.0 

Potassium bromide ... 25.0 

Ferrous sulphate 25.0 

Strychnine sulphate .. 22.5 



Parts. 

Ammonium chloride . . 20 

Sodium chloride 20.0 

Arsenious acid 2' >.0 

Arsenic acid 20.0 

Ammonium carbonate. 20.0 

Lead acetate 20.0 

Morphine chloride 20.0 

Ferric lactate 16.0 

Oxalic acid 15.0 

Barium chloride 10.0 

Boric acid 10.0 

Benzoic acid 10. 

Calcic sulphide 10.0 

Potassium sulphide... 10.0 

Sodium bicarbonate .. 8.0 

Mercuric chloride 7.5 

Cinchonine sulphate . . 6.7 

Tartar emetic 5.5 



Parts. 
Strychnine nitrate. . . 3.85 
Potassium chlorate . . 3.5 

Atropine 3.0 

Quinine sulphate .... 2.75 

Brucine 2. 25 

Iodine 1.9 

Veratrine 1.0 

Quinine tannate 0. 77 

Quinine 0.5 

Cinchonine 0.5 

Morphine 0. 45 

Mercuric iodide 0.29 

Strychnine 0. 25 

Phosphorus 0.20 

Sulphur 0. 1 9 

Sugar 40.0 

Gum 28.5 



2'f 6 GENERAL MEDICAL CHEMISTRY. 

The following substances are soluble in glycerin in all proportions : 



Bromine. 
Ferrous iodide. 
Antimony trichloride. 
Ferric chloride. 
Sodium hypochlorite. 
Potassium hypochlorite. 
Sulphuric acid. 



Nitric acid. 
Hydrochloric acid. 
Phosphoric acid. 
Acetic acid. 
Tartaric acid. 
Citric acid. 
Lactic acid. 



Ammonia. 
Potassium hydrate. 
Sodium hydrate. 
Codeine. 
Silver nitrate. 
Mercurous nitrate. 



When glycerin is heated, a portion distils unaltered between 275° — 
280°; the greater part, however, is decomposed, giving off acrolein, acetic 
acid, carbon dioxide, and combustible gases. It may be distilled without 
decomposition in a current of superheated steam, the temperature being 
maintained between 288° — 315°. 

Platinum black oxidizes glycerin with the production, finally, of water 
and carbon dioxide; oxidized by manganese dioxide and sulphuric acid, 
it yields carbon dioxide and formic acid. The action of nitric acid on 
glycerin varies with the conditions; if a layer of glycerin, diluted with 
water, is floated on nitric acid of sp. gr. 1.5, glyceric acid is formed; by 
the action of a mixture of concentrated nitric and sulphuric acids on 
glycerin, nitro-glycerin (q. v.) is formed. 

When heated with an alkaline hydrate, it forms a mixture of potas- 
sium formiate and acetate. Phosphoric anhydride removes from it the 
' elements of water, to form acrolein (q. v.); the same change is produced 
when glycerin is heated with sulphuric acid or with potassium hydro- 
sulphate. When heated with oxalic acid, it is decomposed into carbon 
dioxide and formic acid. 

Uses. — Glycerin is very extensively used in the arts and in medicine. 
Being unctuous to the touch, and neither volatile nor prone to become 
gummy, it is used to protect substances from contact with air; its non- 
volatility and power of attracting moisture from the air renders it invalu- 
able for maintaining the moisture of certain bodies, as modeller's clay, dye- 
stuffs, etc. It is also largely used in weaving, dyeing, calico-printing, 
printing; to prevent mouldiness in various substances; as a solvent; in 
the manufacture of nitro-glycerin, dynamite, etc. 

Its neutrality, unctuousness, and non-volatility render it applicable to 
many pharmaceutical uses. As a solvent, in the preparation of glyceroles, 
and of semi-solid cerates, glycerates; for the prevention of mould in solu- 
tions of morphia, etc., etc. 

The glycerin used for medicinal purposes should respond to the fol- 
lowing tests: 1st, its specific gravity should not vary much from that 
given above; 2d, it should not rotate polarized light; 3d, it should not 
turn brown when heated with sodium hydrate; 4th, it should not be col- 
ored by hydrogen sulphide; 5th, when dissolved in its own weight of 
alcohol containing one per cent, of sulphuric acid, the solution should be 
clear; 6th, when mixed with an equal volume of sulphuric acid of sp. 
gr. 1.83, it should form a limpid, brownish mixture, but should not give 
off gas. 



Malic Acid, C 4 H 6 6 . 

This acid is the only one of those derivable from the glycerin series 
which is of medical importance. It exists in the vegetable kingdom, 
either free or in combination with potassium, sodium, calcium, magnesium, 



ETHERS OP GLYCERIC. 277 

or organic bases; principally in fruits such as apples, cherries, etc.; ac- 
companied by citrates and tartrates. 

It may be obtained from the unripe berries of the mountain ash. The 
expressed juice is heated and calcium carbonate added as long as there is 
effervescence; the liquid is allowed to cool, filtered, plumbic nitrate added, 
and set aside until the plumbic nitrate crystallizes. The crystals are 
slightly washed with cold water, dissolved, the solution decomposed with 
hydrogen sulphide, filtered, and the filtrate evaporated over the water- 
bath. 

The acid obtained by this process crystallizes in brilliant, prismatic 
needles; odorless; having a strongly acid taste; fusible at 100°; lose 
water at 140°; deliquescent, very soluble in water and in alcohol. Its 
aqueous solutionis laevogyrous: [«] d_ — 5°. When heated to 175° — 180° 
malic acid is decomposed into water and maleic acid. 

There exists another modification of malic acid, formed by the action 
of nitrous acid upon aspartic acid, which differs from this in being opti- 
cally inactive, in its fusing-point, 133°, and in the properties of its salts. 

COOH 

I 
OHOH 

As indicated by the formula of constitution , malic acid is 

CH a 

COOH 

triatomic and dibasic. 

The malates when taken into the economy, are oxidized to carbonates. 



ETHERS OF GLYCERIN. 

Glycerides. 

Being a triatomic alcohol, glycerin contains three groups OH, the hy- 
drogen of each of which may be replaced by an acid radical; or, more 
properly speaking, one, two, or three of these oxhydryl groups may be re- 
moved, leaving a univalent, divalent, or trivalent remainder, which may 
replace the hydrogen of one, two, or three molecules of a monobasic acid 
to form three series of ethers: 

CH 2 OH CH 2 -O-0 2 H 3 O CH 2 -0-C 3 H 3 CH 2 - 0-C 2 H 3 

II I I 

CHOH CHOH CH-0-C 2 H 3 CH-0-C 2 H 3 O 

CH 2 OH CH 2 OH CH 2 OH CH a -0-C 2 H,0 

Glycerin. Manoactin. Diacetin. Triacetin. 

Of the many substances of this class, only a few, principally those en- 
tering into the composition of the neutral fats, require consideration here. 

Tributyrin, C 3 H 3 (0,C 4 H 7 0) 3 — exists in butter. It may also be ob- 
tained by heating glycerin with butyric and sulphuric acids. It is a 
liquid, having a pungent odor and taste; is exceedingly prone to decom- 
position, with liberation of butyric acid. 



278 GENERAL MEDICAL CHEMISTRY. 

Trivalerin, C 3 H B (0,C 5 H 9 0) 3 — exists in the oil of some maritime 
mammalia, and is identical with the phocenine of Chevreul. 

Trieaproin, S H 5 (0,C 6 H n O) 3 --Tricaprylin ; C 3 H 5 (0.0 8 H ]5 0) 3 , and 
Trieaprin, C 3 H 5 (0,C 10 H 19 O) 3 — exist in small quantities in milk, butter 
and cocoa-butter. 

Tripalmitin, C 3 H 5 (O,C 10 H 31 O) 3 — exists in most animal and vegetable 
fats, notably in palm-oil ; it may also be obtained by heating glycerin 
with eight to ten times its weight of palmitic acid for eight hours at 250°. 
It forms crystalline plates, very sparingly soluble in alcohol, even when 
boiling; very soluble in ether. It fuses at 50° and solidifies again at 
46°. 

Trimargarin, C 3 H 5 (0,C 17 H 33 0) 3 — has probably been obtained arti- 
ficially as a crystalline solid, fusible at 60°, solidifiable at 52°. The sub- 
stance formerly described under this name as a constituent of animal fats 
is a mixture of tripalmitin and tristearin. 

Tristearin, C 3 H 5 (O,0 18 H 35 O) 3 — is the most abundant constituent 
of the solid fatty substances. It is prepared in large quantities as an 
industrial product in the manufacture of stearin candles, etc., but is ob- 
tained in a state of purity only with great difficulty. 

In as pure a form as readily obtainable, it forms a hard, brittle, crystal- 
line mass ; fusible at 68°, solidifiable at 61°; soluble in boiling alcohol, al- 
most insoluble in cold alcohol, readily soluble in ether. 

Triolein, C 8 H 5 (0,C 18 H 33 0) 3 — exists in varying quantity in all fats, 
and is the predominant constituent of those which are liquid at ordinary 
temperatures, it may be obtained from animal fats by boiling with alcohol, 
filtering the solution, decanting after twenty-four hours' standing; freez- 
ing at 0°, and expressing. 

It is a colorless, odorless, tasteless oil ; soluble in alcohol and ether, 
insoluble in water; sp. gr. 0.92. 

Trinitro-glycerin — nitro-glycerin — C 3 H 5 (ON0 2 ) 3 . — This sub- 
stance, which is used as an explosive, both pure and mixed with other 
substances in dynamite, giant powder, etc., is obtained by the combined 
action of sulphuric and nitric acids upon glycerin. Fuming nitric acid is 
mixed with twice its weight of sulphuric acid in a cooled earthen vessel; 
thirty-three parts by weight of the mixed acids are placed in a porcelain 
vessel, and five parts of glycerin, of 31° Beaume, are gradually added 
with constant stirring, while the vessel is kept well cooled ; after five 
minutes the whole is thrown into five to six volumes of cold water; the 
nitro-glycerin separates as a heavy oil which is washed with cold water. 

Nitro-glycerin is an odorless, yellowish oil ; has a sweetish taste; sp. 
gr. 1.6; insoluble in water, soluble in alcohol and ether; not volatile ; 
crystallizes in prismatic needles when kept for some time at 0°; fuses 
again at 8°. 

When pure nitro-glycerin is exposed to the air at 30° for some time, 
it decomposes without explosion and with production of glyceric and 
oxalic acids. When heated to 100° it volatilizes without decomposition; 
at 185° it boils, giving off nitrous fumes; at 217° it explodes violently; if 
quickly heated to 257°, it assumes the spheroidal form and volatilizes with- 
out explosion. Upon the approach of flame at low temperatures it ig- 
nites and burns with slight decrepitations. When subjected to sudden 
shock, it is suddenly decomposed into carbon dioxide, nitrogen, vapor of 
water and oxygen, the decomposition being attended with a violent ex- 
plosion. 

In order to render this explosive less dangerous to handle, it is now 



FIXED VEGETABLE OILS. 279 

usually mixed with some inert substance, usually diatomaceous earth, in 
which form it is known as dynamite, etc. 

When taken internally, nitro-glvcerin is an active poison, producing 
effects somewhat similar to those of strychnine ; even in drop-doses, di- 
luted, it causes violent headache, fever, intestinal pain, and nervous symp- 
toms. It has been latterly used as a therapeutic agent, and has been 
used by the homoeopaths under the name of glonoin. 



NEUTRAL OILS AND PATS. 

These are mixtures in varying proportions of tripalmitin, tristearin, 
and triolein, with small quantities of other glycerides, coloring and odor- 
ous principles, which are obtained from animal and vegetable bodies. 
The oils are fluid at ordinary temperatures, the solid glycerides being in 
solution in an excess of the liquid triolein. The fats, owing to a less pro- 
portion of the liquid glyceride, are solid or semi-solid at the ordinary tem- 
perature of the air; members of both classes are fluid at sufficiently high 
temperatures, and solidify when exposed to a sufficiently low temperature. 
They are, when pure, nearly tasteless and odorless, unctuous to the touch, 
insoluble in and not miscible with water, upon which they float; combus- 
tible, burning with a luminous flame; when rubbed upon paper they ren- 
der it translucent. When heated with the caustic alkalies or in a current 
of superheated steam, they are saponified, i. e., decomposed into glycerin 
and a fatty acid. If the saponification be produced by an alkali, the 
fatty acid combines with the alkaline metal to form a soap (q. v.). 

Most of the fats and many of the oils, when exposed to the air, absorb 
oxygen, are decomposed with liberation of volatile, fatty acids, and ac- 
quire an acid taste and odor, and an acid reaction. A fat which has 
undergone these changes is said to have become rancid. Manv of the 
vegetable oils are, however, not prone to this decomposition. Some of 
them, by oxidation on contact with the air, become thick, hard and dry, 
formiug a kind of varnish over surfaces upon which they are spread; 
these are designated as drying or siccative oils. Others, although they 
become more dense on exposure to air, become neither dry nor gummy; 
these are known as non-drying, greasy, or lubricating oils. 

Under ordinary conditions, oils and melted fats do not mix with 
water, and, if shaken with that fluid, form a temporary milky mixture, 
which, on standing for a short time, separates into two distinct layers, 
the oil floating on the water. In the presence, however, of small quanti- 
ties of certain substances, such as albumen, pancreatin (q. v.), ptyalin. 
etc., the milky mixture obtained by shaking together oil and water does 
not separate into distinct layers on standing; such a mixture, in which 
the fat is held in a, permanent state of suspension in small globules in a 
watery fluid, is called an emulsion. 



Fixed Vegetable Oils. 

These substances are designated as "fixed," to distinguish tnem from 
other vegetable products having an oily appearance, but which differ fronii 
the true oils in their chemical composition and in their physical proper- 
ties, especially in that they are volatile without decomposition, and are< 



280 GENERAL MEDICAL CHEMISTRY. 

obtained by distillation, while the fixed oils are obtained by expression, 
with or without the aid of a moderate heat. The fixed oils form two classes, 
the greasy and drying oils (see above). 

In testing the purity of the oils, advantage is taken of the specific 
gravity, point of congelation, and of the action of reagents: 1st, sulphuric 
acid — about twenty drops of the oil are placed on a watch-glass over a 
white surface, and a drop of concentrated sulphuric acid is added; after- 
ward the whole is stirred with a glass rod; the changes of color observed 
with the principal oils before and after stirring vary with the different 
oils. 2d, Pontefs reagent, made by dissolving six parts of mercury in 
7.5 parts of nitric acid of 36° in the cold. One part of this reagent is 
well shaken with twelve parts of the oil, and the mixture set aside for 
twelve hours; the greasy oils are completely solidified, while the drying 
oils remain fluid. 3d, Hauchecornd s reagent — three parts of nitric acid 
of 40°, diluted with one part of distilled water; one gram of this reagent 
is mixed with three grams of the oil and shaken in a test-tube. 

Palm-oil is the product of a species of palm growing on the Guinea 
coast, in the West Indies, and South America. It is a reddish yellow 
solid at ordinary temperatures, has a bland taste and an aromatic odor. 
It saponifies readily, and is used in the manufacture of palm-soap. It is 
usually acid, and contains free glycerin from spontaneous decomposition. 

Rape-seed oil and colza-oil are produced from the seeds of various 
species of Prassica y yellow, limpid oils, having a strong odor and a 
disagreeable taste. They are used for burning in lamps and for the 
manufacture of soft-soaps. 

Croton-oil — Oleum tiglii (U. S.) — Oleum crotonis (Br.) — is one of the 
few fixed oils possessed of distinct medicinal properties. It varies much 
in color and activity, according to its source; that which is obtained from 
the East is yellowish, liquid, transparent, and much less active than that 
prepared in Europe from the imported seeds, which is darker, less fluid, 
caustic in taste, and wholly soluble in absolute alcohol. Croton-oil con- 
tains, besides the glycerides of oleic, crotonic and fatty acids, about four 
per cent, of a peculiar principle called by Schlippe crotonol, to which the 
oil owes its vesicating properties; it also contains an alkaloid-like sub- 
stance, also existing in castor-oil, called ricinine. None of these bodies, 
however, are possessed of the drastic powers of the oil itself. 

Peanut-oil — Ground-nut oil — an almost colorless oil, very much re- 
sembling olive-oil, in place of which it is frequently used for culinary pur- 
poses, intentionally or otherwise. It is readily saponifiable, yielding two 
peculiar acids, arachdlc and hypoga'lc (see Olive-oil). 

Cocoanut-oil or butter, not to be confounded with cocoa-butter, is at 
ordinary temperatures a white solid resembling lard; fuses at about 20°, 
and solidifies at about 10°; it has a pleasant odor and a bland taste. It 
is readily saponifiable, yielding a hard sodium soap. It easily becomes 
rancid. It is said to contain an acid, called cocinic, or cocostearic. 

Almond-oil — Oleum amygdalm dulcis (U. S.) — Oleum amygdalm (Br.) 
— a light yellow oil, very soluble in ether, soluble in twenty-four parts of 
alcohol; nearly inodorous; has a bland, sweetish taste. It is largely used 
in pharmacy, in the preparation of ointments, and in the arts in soap 
manufacture. The pure oil has no odor of bitter almonds; is completely 
solidified by Pontet's reagent; is colored peach-red, but not green, by a 
mixture of nitric and sulphuric acids; produces no coloration when its 
ethereal solution is shaken with a concentrated alcoholic solution of silver 
nitrate, and the mixture set aside in the dark for twelve hours. 



ANIMAL OILS. 281 

Olive-oil — Oleum olivce (U. S., Br.) — a well-known oil of a yellow or 
greenish yellow color, almost odorless, and of a bland and sweetish taste. 
The finest grades have a yellow tinge and a faint taste of the fruit; they 
are prepared by cold pressure; they are less subject to rancidity than the 
lower grades. Olive-oil is very frequently adulterated, chiefly with poppy- 
oil, sesame-oil and peanut-oil; the presence of the first is detected by 
Pontet's reagent, which converts pure olive-oil into a solid mass, while an 
oil adulterated with a drying oil remains semi-solid. A contamination 
with oil of sesame is indicated by the production of a green color, with a 
mixture of nitric and sulphuric acids. Peanut-oil, an exceedingly common 
adulterant in this country, is recognized by the point of congelation, or 
more delicately by the following method: ten grams of the oil are 
saponified; the soap is decomposed with hydrochloric acid; the liberated 
fatty acids dissolved in 50 c.c. of strong alcohol; the solution precipitated 
with lead acetate; the precipitate washed with ether; the residue decom- 
posed with hot dilute hydrochloric acid; the oily layer separated and 
extracted with strong alcohol; the alcoholic fluid, on evaporation, yields 
crystals of aracha'lc acid, if the oil contains peanut-oil. 

Cotton-seed oil is also added to olive-oil in this country ; its presence 
is detected, like that of other drying oils, by the formation of a pasty 
magma in place of a solid mass when the oil is subjected to the action of 
Pontet's reagent. 

Cocoa-butter — Oleum theobromm (U. S., Br.) — is at ordinary tempera- 
tures a whitish or yellowish solid of the consistency of tallow, and hav- 
ing an odor of chocolate and a pleasant taste; it does not easily become 
rancid. The most reliable test of its purity is its fusing-point, which 
should not be much below +33°. 

Linseed-oil — Flaxseed-oil — Oleum lini (U. S., Br.) — is prepared on a 
large scale as an industrial product, and is largely used by painters. Its 
drying qualities are increased by charging it with lead oxide, by boiling 
with litharge (boiled oil). The raw oil has a disagreeable odor and a 
nauseous taste, is dark yellowish brown in color, and readily soluble in 
ether and hot alcohol. In this oil oleic acid is, at least partially, replaced 
by another fluid acid, linoleic acid, which, when exposed to the air, gradu- 
ally absorbs oxygen and becomes thick and finally solid. 

Castor-oil — Oleum ricini (U.S., Br.) — is usually obtained by expres- 
sion of the seeds, although in some countries it is prepared by decoction 
or by extraction with alcohol. It is a thick, viscid, yellowish oil, has a faint 
odor and a nauseous taste. It is more soluble in alcohol than any other 
fixed vegetable oil, and is also very soluble in ether. It saponifies very 
readily. Ammonia separates from it a crystalline solid, fusible at 66° — 
ricinolamide. Hot nitric acid attacks it energetically, and finally converts 
it into suberic acid. 



Animal Oils. 

The principal oils of animal origin used in the arts and in medicine are 
the following:: 

Whale-oil — Train-oil — obtained by trying out the fat or blubber of the 
" right whale " and of other species of balw?ice. It is of sp. gr. 0.924; at 
15°; brownish in color; becomes solid at about 0°; has a very nauseous taste 
and odor; it may be deodorized to a certain extent by passing through it 
a current of steam heated to 160°. It is colored yellow by sulphuric 



282 GENERAL MEDICAL CHEMISTRY. 

acid; with Pontet's reagent it forms a yellow salve, which slowly turns 
brown; chlorine blackens it immediately. 

Sperm-oil is obtained, along with spermaceti, from the cranial cavities 
of the cachalot or sperm-whale. It is a clear, transparent, orange-yellow 
oil; sp. gr. 0.884 at 15°; at — 8° it deposits crystals of a solid fat. It 
saponifies with difficulty, and is solidified by Pontet's reagent. 

Porpoise-oil y a pale yellow, neutral oil; sp. gr. 0.937 at 16°; solidifies 
at -15°. 

Dolphin-oil / a pale yellow, neutral oil; sp. gr. 0.918 at 20°; when 
cooled it deposits crystals at + 5° and again at — 3°. 

Seal- oil ; a dark brown, viscid oil, having a disgusting odor; sp. gr. 
0.9317 at 11°. 

Shark-oil / a pale yellow, stinking oil of sp. gr. 0.870 at 15°. 

These oils are used in the manufacture of soft soaps, for illumination, 
and ill dressing 1 leather. 

NeaCs-foot oil — Oleum bubulum (U.S.) — is obtained by the action of 
boiling water upon the feet of neat cattle, horses, and sheep, deprived of 
the flesh and hoofs. It is straw yellow or reddish yellow, odorless, not 
disagreeable in taste, not prone to rancidity, does not solidify at quite 
low temperatures; sp. gr. at 15°, 0.916. It is bleached, not colored, by 
chlorine; in which it differs from fish- and whale-oils. It is used as a lubri- 
cant and in pharmacy. 

Lard-oil, obtained in large quantities in the United States as a by- 
product in the manufacture of candles, etc., from pigs' fat. A light 
yellow oil, used principally as a lubricant; it is not colored by sulphuric 
acid, but is colored brown by a mixture of sulphuric and nitric acids. 

Tallow-oil — obtained by expression with a gentle heat from the fat of 
the ox and sheep. Sp. gr. 0.9003; light yellow in color. Colored brown 
by sulphuric acid. Formerly this oil, under the trade-name of "oleic 
acid," was simply a by-product in the manufacture of stearine candles; 
of late years, however, it is specially prepared for the manufacture of 
oleo-margarine. 

Cod-liver oil — Oleum morrhum (U. S., Br.) — is obtained principally in 
Norway and Newfoundland, from the livers of codfish, either by ex- 
traction with water heated to about 80°, or by hanging the livers in the 
sun and collecting the oil which drips from them. There are three com- 
mercial varieties of this oil: a. JBrown. — Dark brown, with greenish reflec- 
tions; sp. gr. 0.928 at 15°; has a disagreeable, irritating taste; faintly acid; 
does not solidify at — 13°. b. Pale brown. — Of the color of Malaga wine; 
sp. gr. 0.924; has a peculiar odor and a fishy, irritating taste; strongly 
acid. c. Pale. — G-olden yellow; sp. gr. 0.928 at 15°; deposits a white fat 
at — 13°; has a fresh odor, slightly fishy, and a not unpleasant taste, with- 
out after-taste. 

Pure cod-liver oil, with a drop of sulphuric acid, gives a bluish violet 
aureole, which gradually changes to crimson, and later to brown. A drop 
of fuming nitric acid dropped into the oil is surrounded by a pink aureole 
if the oil be pure; if largely adulterated with other fish-oils, the pink 
color is not observed and the oil becomes slightly cloudy. Fresh cod- 
liver oil is not colored by rosaniline. If a third of the oil is distilled, the 
distillate becomes solid; while if it be contaminated with vegetable oils, 
the distillate becomes liquid. 

Cod-liver oil contains, besides the glycerides of oleic, palmitic and 
stearic acids, those of butyric and acetic acids, certain biliary principles 
(to whose presence the sulphuric acid reaction given above is probably 



SOLID ANIMAL FATS. 



283 



due), a phosphorized fat of undetermined composition, small quantities 
of bromine and iodine, probably in the form of organic compounds, a pe- 
culiar fatty acid called gadinic acid, which solidifies at 00°, and a brown 
substance called gaduin or gadinine. 

To which, if to any of these substances, cod-liver oil owes its value as 
a therapeutic agent, is still unknown, although many theories have been 
advanced. Certain it is, however, that one of the chief values of this oil 
is as a food in a readily assimilable form. 



SOLID ANIMAL FATS. 



Condition in the body. — The glycerides of stearic, palmitic and oleic 
acids exist, in health, in all, or nearly all, parts of the body; in the fluids 
in solution or in suspension, in the form of minute oil-globules; incorpo- 
rated in the solid or semi-solid tissues, or deposited in collections in cer- 
tain locations, as under the skin, inclosed in cells of connective tissue, in 
which the mixture of the three glycerides is in such proportion that the 
contents of the cells are fluid at the temperature of the body. • 

The total amount of fat in the body of a healthy adult is from 2.5 to 
5 per cent, of the body-weight, although it may vary considerably from 
that proportion in conditions not, strictly speaking, pathological. The 
approximate quantities of fat in 100 parts of the various tissues and fluids, 
in health, are the following: 



Urine ? 

Perspiration 0.001 

Vitreous humor 0.002 

Saliva 0.02 

Lymph 0.05 

Synovial fluid 0.06 

Amniotic fluid 0.2 

Chyle 0.3 

Mucus 0.4 



Blood 0.4!Cortex of brain 5.5 

Cartilage 1.3JBrain... 8.0 



Bone 1 

Bile 1.4 

Crystalline lens 2.0 

Liver 2.4 

Muscle 3.3 

Hair 4.2 

Milk 4.3 



Hen's egg 1 11.6 

White matter of brain. . 20 . 

Nerve-tissue 22. 1 

Spinal cord 23 . 6 

Fat-tissue 82.7 

Marrow 96.0 



The amount of fat in the body, under normal conditions, is usually 
greater in women and children than in men; generally greater in middle 
than in old age, although in some individuals the reverse is the case; 
greater in the inhabitants of cold climates than in those of hot countries. 

In wasting from disease and from starvation the fats are rapidly ab- 
sorbed, and are again as rapidly deposited when the normal condition of 
affairs is restored. 

Besides as a result of the tendency to corpulence, which in some in- 
dividuals amounts to a pathological condition, fats may accumulate in 
certain tissues as a result of morbid changes. This accumulation mav be 
due either to degeneration or to infiltration. In the former case, as when 
muscular tissue degenerates in consequence of long disuse, the natural 
tissue disappears and is replaced by fat; in the latter case, as in fatty in- 
filtration of the heart, oil-globules are deposited between the natural 
morphological elements, whose change, however, may subsequently take 
place by true fatty degeneration due to pressure. Fatty degeneration 
of the liver and of other organs occurs also in phthisis, chronic heart and 
lung affections, as a result of overfeeding, from the abuse of alcoholic 
stimulants, and from the action of certain poisons, especially of phos- 
phorus. Tumors composed of adipose tissue occur and are known as 
" lipomata." 



284 GENERAL MEDICAL CHEMISTRY. 

The greater part of the fat of the body enters it as such with the food; 
not unimportant quantities are, however, formed in the body, and that 
from the albuminoid as well as from the starchy and saccharine constitu- 
ents of the food. By what steps this transformation takes place is still 
uncertain, although there is abundant evidence that it does occur. 

Those fats taken in with the food are unaltered by the digestive fluids, 
except in that they are freed from their enclosing membranes in the 
stomach, until they reach the duodenum; here, under the influence of the 
pancreatic juice, the major part is converted into a fine emulsion, in which 
form it is absorbed by the lacteals. A smaller portion is saponified, and 
the products of the saponification, free fatty acids, soaps, and glycerin, 
subsequently absorbed by lacteals and blood-vessels. 

The service of the fats in the economy is undoubtedly as a producer of 
heat and force by its oxidation; and by its low power of conducting heat, 
and the position in which it is deposited under the skin, as a retainer of 
heat produced in the body. The fats are not discharged from the system 
in health, except the excess contained in the food over that which the 
absorbents are capable of taking up, which passes out with the faeces, a 
small quantity distributed over the surface in the perspiration and seba- 
ceous secretion (which can hardly be said to be eliminated) and a mere 
trace in the urine. 

Animal Fats used in the Arts and in Pharmacy. — The prin- 
cipal of these are lard, tallow, and butter. 

Lard — Adeps (U. S.) — is the fat of the hog freed from connective tis- 
sue. It is white, almost odorless, almost tasteless, soft; fusible at 38°; 
readily saponifiable by alkalies; not prone to rancidity if properly prepared. 

Tallow, the purified fat of the ox or sheep; is rather harder than lard; 
white, tasteless, and odorless when pure; fuses at about 44°; and solid- 
ifies at about 37°. 

Butter, the fat of milk, separated and made to agglomerate by agita- 
tion, and more or less salted to insure its keeping. It consists of the 
glycerides of stearic, palmitic, oleic, butyric, capric, caprylic, and caproic 
acids, with a small amount of coloring matter, more or less water and salt 
and casein. Good, natural butter contains eighty to ninety per cent, of 
fat, six to ten per cent, of water, two to five per cent, of curd, and two to 
five per cent, of salt; fuses at from 32.8° to 34.9°. 

Butter is very liable to adulterations, the chief adulterants being ex- 
cess of water and salt, starch, animal fats other than those of butter, 
artificial coloring matters. 

Excess of salt and water are usually worked in together, the former 
up to fourteen per cent, and the latter to fifteen per cent. To determine 
the presence of an excess of water, about four grams of the butter, taken 
from the middle of the lump, are weighed in a porcelain capsule, in which 
it is heated over the water-bath, as long as it loses weight; it is then 
weighed again; the loss of weight is that of the quantity of water in the 
original weight of butter, less that of the capsule. The proportion of salt 
is determined by incinerating a weighed quantity of butter and determin- 
mining the chlorine in the ash by the nitrate of silver method (see Sodium 
Chloride). Roughly, the weight of the ash may be taken as salt. Starch 
is detected by spreading out a thin layer of the butter, adding solution of 
iodine, and examining under the microscope for purple spots. 

To determine the presence of foreign fats, the best method is that of 
Angell and Hehner. A pear-shaped bulb is made by blowing a small 
globe in the end of a piece of glass tubing of one-fourth inch diameter 



soaps. 285 

and drawing* off a tapering neck very near the bulb, the diameter of which 
should be about one-half inch; enough mercury is then placed in the bulb 
to make the whole weigh 3.4 grams, and the open end closed by fusion. 
To use this little apparatus, twenty to thirty grams of the butter to be 
tested are melted in a beaker on the water-bath, and, when quite fluid, 
poured into a test-tube three-fourths inch in internal diameter and six 
inches long, until the tube is filled to within two inches of the top; the 
tube is then kept warm and upright until the fat has separated in a clear 
layer above the water, etc., after which it is solidified by immersion in 
water at 15°; the surface should only be slightly depressed. The test- 
tube with the solidified butter is suspended in a large beaker of cold 
water; the small bulb is laid upon the surface of the fat, which should be 
one and one-half inch below the surface of the water in the beaker, and 
a thermometer is suspended near the test-tube. The water is now heated 
until the globular part of the bulb has just sunk below the surface of the 
fat, at which point the standing of the thermometer is read off; this is the 
"sinking-point" of the butter, and should be from 34.3° to 36.3°. Oleo- 
margarine, or butterine, has a lower sinking-point, and butter adulterated 
with fats a hisrher one. 



"D' 



Soaps. 

These compounds, which have been known from time immemorial, are 
the metallic salts of stearic, palmitic, and oleic acids; those of potassium, 
sodium, and ammonium are soluble in water, while those of other metals 
are insoluble; those of potassium and sodium are also soluble in alcohol 
and in ether. The sodium soaps are hard, and those of potassium soft. 

Soap is made from almost any oil or fat, the best from olive-oil, or pea- 
nut- or palm-oil, and lard. The first step in the process of manufacture is 
the saponification of the fat, which consists in the decomposition of the 
glyceric ethers into glycerin and the fatty acids, and the combination of 
the latter with an alkaline metal; it is usually effected by gradually add- 
ing the fluid fat to a weak boiling solution of caustic soda or potassa to 
saturation. From this weak solution the soap is separated by " salting," 
which consists in adding, during constant agitation, a solution of caustic 
alkali, heavily charged with common salt, until the soap separates in 
grumous masses, which float upon the surface and are separated. Finally 
the soap is pressed to separate adhering water, fused, and cast into 
moulds. 

The varieties of soaps used in the arts and in medicine are numerous. 

Yellow soap is made from tallow or other animal fat, and about one- 
third weight of rosin subsequently added. 

White castile soap — Olive-oil soap (Sapo f U. S.; Sapo durus, Br.), is 
pale grayish white in color, hard, dry, not greasy; strongly alkaline; very 
soluble in alcohol and water; contains twenty-one per cent, of water. 
A marbled variety of the same soap is made by using a soda containing 
ferruginous matter and agitating the saponified fat at the proper time; it is 
harder than the white variety, and contains less water — fourteen per cent. 
A soft or potash soap is also made from olive-oil, and, like other soft 
soaps, contains an excess of alkali and glycerin; it is the Sapo mollis 
(U. S.). Olive-oil soaps are usually imported from France and Spain. 

Almond-oil soap is the officinal soap of the French Codex, and con- 
tains glycerin and an excess of alkali. 



286 GENERAL MEDICAL CHEMISTRY. 

JEmplastrum plumbi (U. S., Br.) is simply a lead-soap, prepared by 
saponifying olive-oil, or a mixture of olive-oil and lard with litharge. 

Linimentum calcis (U. S., Br.) is a mixture of calcium soap with olive- 
or flaxseed-oil in excess. 

All the soaps are decomposed by even weak acids, with liberation of 
the fatty acids; by compounds of the alkaline earths, with formation of 
an insoluble soap; and in the same way by most of the metallic salts. 



Phosphorized Fats. 

Lecithins. — That brain-tissue contains phosphorus was known as 
early as 1779, and that this phosphorus exists in combination in a fat-like 
material was determined in the early part of the present century. In 
1851 Gobley described a fatty material which he obtained from the yolks 
of eggs, and which he called lecithin; later, in 1865, Liebreich described 
a substance also containing phosphorus, which he obtained from brain- 
tissue, and which he designated as protogon. 

Most later authors have considered protogon as being a mixture of 
lecithin and another substance called cerebrin, although Gamgee ad- 
vances strong grounds for its admission as a distinct substance. The 
study of the constituents of brain- and nerve-tissue is one surrounded with 
great difficulties, and has led as yet to but few results sufficiently well es- 
tablished for adoption in a work of this nature. 

That lecithin, however, or rather a number of lecithins, exist in brain- 
tissue, in the yolks of hens' eggs, in fish-roes, etc., may be considered as 
definitely settled. 

These substances are of very complex constitution ; they yield, on de- 
composition, neurine (see p. 206), stearic, palmitic, or oleic acid, and a 
peculiar acid, called from its composition, glycerophosphoric acid. They 
are, therefor, glycerophosphoric acid in which the remaining hydrogens of 
the glycerin are replaced by radicals of fatty acids, and the remaining 
oxhydryls of the phosphoric acid by neurine: 



CH,-OH CH,-0(C„H,.0)" 

CH-OH CH-0 (C„H„0)' 

Jtt opo/° h Oh _opo/° hn < ch °> 

Glycerophosphoric acid. Stearine lecithin. 

The lecithins are yellowish white, waxy, hygroscopic solids, imper- 
fectly crystalline, soluble in ether and alcohol, insoluble in water, in 
which they swell like starch; when ignited they burn, leaving a residue 
of metaphosphoric acid and carbon. They form compounds with certain 
salts, as platinic chloride, and with acids. They are readily decomposed, 
yielding the products mentioned above. 



ILLUMINATING-GAS. 287 

THIRD SERIES OF HYDROCARBONS. 

Series C n H. in _ a . 

The terms of this series at present known are: 

Acetylene C 2 H 2 I Crotonylene C 4 H 6 1 Rutylene Ci H 18 

Allylene C 3 H 4 | Valerylene C 6 H 8 I Benylene CisHog 



Acetylene. 

JEthene, C 2 H 2 — was discovered by Davy. It exists as a constituent 
of coal-gas ; it is formed as a product of the decomposition, by heat and 
otherwise, of a number of organic substances, notably of hydrocarbons, 
ether, chloroform, etc. It is best prepared by passing a slow current of 
coal-gas through a narrow tube through which induction sparks are pass- 
ing, directing the gas through a solution of cuprous chloride, and collect- 
ing and decomposing the precipitate with hydrochloric acid. 

A most interesting method of its formation is that by direct synthesis, 
discovered by Berthelot: a slow current of hydrogen is passed through a 
glass globe in which are the carbon-points of an electric light; the escap- 
ing gas contains acetylene formed by the direct union of carbon and 
hydrogen. 

Acetylene is a colorless gas, rather soluble in water; it has a peculiar, 
disagreeable odor, which is observed when a Bunsen burner burns within 
the tube, and when a piece of platinum foil is incandescent in vapor of 
ether; it burns with a white, luminous flame. 

When mixed with oxygen it explodes violently on the approach of a 
flame, a deposit of carbon being formed if the amount of oxygen be defi- 
cient. It unites with nitrogen under the influence of the electric dis- 
charge, to form hydrocyanic acid. It combines with hydrogen to form 
ethylene. Mixed with chlorine it detonates violently even in diffuse day- 
light, and without the application of heat. It may be made to unite 
with itself to form its superior polymeres: 

C 2 H 2 C 6 H 6 C 8 H 8 C 10 H 10 

Acetylene. Benzene. Styrolene. Naphthydrene. 

Its most characteristic property is that of forming a blood-red precipi- 
tate of cuproso-acetyl oxide when it is passed through an ammoniacal 
solution of cuprous chloride, a reaction by which the presence of traces 
of this gas may be detected; similar compounds are formed with other 
metals. These precipitates, when dried, explode violently when sub- 
jected to shock, and it is probable that explosions which sometimes occur 
without any apparent cause, in pipes through which illuminating-gas is 
conducted, especially if of brass or copper, are due to their formation. 



Illuminating-Gas. 

Illuminating-gas is now manufactured by a variety of processes, 
almost every gas company using some peculiar modification of the 
method, or of the nature and proportion of the raw materials; thus, we 
have gas made from wood, from coal, from fats, from petroleum, and by 



288 



GENERAL MEDICAL CHEMISTRY. 



the decomposition of water and subsequent charging of the gas with 
the vapor of naphtha. The typical process is that in which the gas is 
produced by heating cannel or other bituminous coal to bright redness 
in retorts. As it issues from the retorts, the gas is charged with sub- 
stances volatile only at high temperatures; these are deposited in the 
condensers or coolers, and form coal- or gas-tar. From the condensers 
the gas passes through what are known as " scrubbers " and "lime-puri- 
fiers," in which it is deprived of ammoniacal compounds and other im- 
purities. As it comes from the condensers, coal-gas contains: 



* Acetylene. 

* Ethylene. 

* Marsh-gas. 

* Butylene. 

* Propylene. 

* Benzene. 



* Styrolere. 

* Naphthalene. 

* Acenaphthalene. 

* Fluorene. 

* Propyl hydride. 

* Butyl hydride. 



% Hydrogen. 

f Carbon monoxide. 

+ Carbon dioxide. 

f Ammonia. 

f Cyanogen. 

f Sulphocyanogen. 



f Hydrogen sulphide, 
f Carbon disulphide. 
f Sulphuretted hy- 
drocarbons, 
f Nitrogen, 
f Aqueous vapor. 



In passing through the purifiers the gas is freed of the impurities to 
a greater or less extent, and, as usually delivered to consumers, contains: 



* Marsh-gas. 

* Acetylene. 



* Ethylene 
\ Hydrogen. 



f Nitrogen 
{ Aqueous vapor. 
* Vapors of hydrocarbons. 



f Carbon monoxide. 
f Carbon dioxide. 



Allylene, C 3 H 4 — is a colorless gas, very soluble in alcohol, quite 
soluble in water; has a slightly less disagreeable odor than acetylene; 
burns with a smoky flame. It is obtained by a general reaction used for 
the obtaining of hydrocarbons of this series, which consists in heating the 
monobromine compounds of the corresponding hydrocarbon of the ethy- 
lene series with sodium ethyl oxide: 



C s H s Br 


+ 


C 2 H 6 NaO = 


= NaBr 


+ 


C 2 H 6 HO 


+ C 2 H, 


Monobrom- 
ethylene. 




Sodium 
ethyl oxide. 


Sodium 
bromide. 




Alcohol. 


Acetylene 


C s H 1 Br 


+ 


C 2 H 6 NaO : 


= NaBr 


+ 


C,H 5 HO 


+ C S H, 


Monobrom- 
propylene. 




Sodium 
ethyl oxide. 


Sodium 
bromide. 




Alcohol. 


Allylene. 



It is distinguished from acetylene by forming a gray precipitate with 
mercurous salts, a white one with the silver salts, and a yellow one with 
the cuprous salts. 

Crotonylene, C 4 H 6 — obtained by the general method from monobrom- 
butylene. It is liquid below 15°; boils at about 18°; has a powerful and 
somewhat alliaceous odor; burns with a bright, smoky flame. It has also 
been obtained by distilling erythrite (q. v.) with formic acid. 



* Illuminating constituents. 



f Impurities. 



X Diluent. 



ACIDS DERIVABLE FROM ERYTHRITE. 289 



TETRATOMIC ALCOHOLS. 

Very few of these compounds have yet been obtained. They may be 
regarded as the hydrates of the hydrocarbons C n H 2n _ 2 ; as the glycols are 
the hydrates of the ethylene series. 

Propylphyeite, C 3 H 4 (OH) 4 — is probably the first term of the series, 
although its existence is not yet well established. 

CH 2 OH 

I 
CHOH 

Erythrite — phycite — I =C H. (OH). — a well-defined com- 

CHOH 

I 
CH 2 OH 

pound, was discovered in 1848, as a product of decomposition of ery- 
thrine, C 20 H 22 O 10 , which exists in lichens of the genus rocella. To obtain 
it the lichens are macerated in water; treated with powdered lime; the 
solution filtered after half an hour; the filtrate treated with hydrochloric 
acid; the gelatinous precipitate of erythrine is washed, dried, and intro- 
duced into a Papin's digester with a small quantity of slacked lime, and 
heated to 100° for two hours; the liquid is filtered and slowly evaporated; 
orcine separates first and is removed, afterward erythrite, which is puri- 
fied by recrystallization from boiling alcohol. 

Erythrite crystallizes in large, brilliant prisms; very soluble in water 
and in hot alcohol, almost insoluble in ether; it is sweetish in taste; its solu- 
tions neither affect polarized light, nor reduce Fehling's solution, nor are 
capable of fermentation; it fuses at 120°, and at 300° is partly decom- 
posed, giving off an odor of caramel. Its watery solution, like that of 
sugar, is capable of dissolving a considerable quantity of lime, and from 
this solution alcohol precipitates a definite compound of erythrite and 
calcium. By oxidation with platinum black it yields erythroglucic acid, 
C 4 H 8 5 . With fuming nitric acid it forms a tetranitro compound, which 
explodes under the hammer. 



ACIDS DERIVABLE FROM ERYTHRITE. 

Theoretically erythrite should, by simple oxidation, yield two acids; 
one of the series C n H 2 „0 B , and another of the series C n H 2n ._ Q 6 . Although 
both of these acids are known, only the first, erythroglucic acid, has been 
obtained by oxidation of erythrite: 



CH 2 OH 


COOH 


COOH 


CHOH 

1 


CHOH 
I 


CHOH 
CHOH 


CHOH 
l 


CHOH 

1 


CH 2 0H 


CH 2 OH 


COOH 


Erythrite. 

19 


Erythroglucic acid. 


Tartaric acid 



290 GENERAL MEDICAL CHEMISTRY. 



Tartaric Acids. 

Acidum tartaricum (U. S., Br.), C 4 H 6 O . — There exist four acids 
having the composition C 4 H e 8 ; which differ from each other only in 
their physical properties, and are very readily converted one into another; 
they are designated as: 1st, Right,' 2d, Left; 3d, Inactive tartaric acid/ 
4th, Racemic acid. Right or Dextrotartaric acid crystallizes in large, 
oblique, rhombic prisms, having hemihedral facettes. Solutions of the 
acid and its salts are dextrogyrous. 

Left or Lcevotartaric acid crystallizes in the same form as dextro- 
tartaric acid, only the hemihedral facettes are on the opposite sides, so 
that crystals of the two acids, when held facing each other, appear like the 
reflections one of the other. Its solution and those of its salts are laevo- 
gyrous to the same degree that corresponding solutions of dextrotartaric 
acid are dextrogyrous. 

Racemic acid is a compound of the two preceding; it forms crystals 
having no hemihedral facettes, and its solutions are without action on 
polarized light. It is readily separated into its components. 

Inactive tartaric acid, although resembling racemic acid in its crystal- 
line form and inactivity with respect to polarized light, differs essentially 
from that acid in that it cannot be decomposed into right and left acids, 
and in the method of its production. 

The tartaric acid which exists in nature is the dextrotartaric ; it 
occurs, both free and in combination, in the sap of the vine and in a great 
number of other vegetable juices and fruits; it has not been detected as a 
constituent of animal bodies. Although this is probably the only tartaric 
acid existing in nature, all four varieties may and do occur in the com- 
mercial acid, being formed during the process of manufacture. 

Tartaric acid is obtained in the arts from hydropotassic tartrate, or 
cream of tartar (q. v.). This salt is dissolved in water and the solution 
boiled with chalk until its reaction is neutral; calcic and potassic tartrates 
are formed: 

2(C 4 H 4 6 ,HK) + C0 3 Ca - C 4 H 4 6 Ca + C 4 H 4 6 K a -f H 2 4- C0 2 

Hydro-potassic Calcium Calcium Potassic Water. Carbon 

tartrate. carbonate. tartrate. tartrate. dioxide. 

The insoluble calcic salt is separated and the potassic salt decomposed 
by treating the solution with calcic chloride: 

C 4 H 4 6 K a + CaCl 3 = C 4 H 4 O fi Ca 4- 2KC1 

Potassic Calcium Calcium Potassium 

tartrate. chloride, tartrate. chloride. 

The united deposits of calcium tartrate are suspended in water, decom- 
posed with the proper quantity of sulphuric acid, the solution separated 
from the deposit of calcium sulphate, and evaporated to crystallization. 

The commercial acid is liable to contamination with sulphuric acid, 
lead and calcium compounds, from which it may be freed by recrystalliza- 
tion. When sufficiently pure for pharmaceutic purposes, its solution is 
not affected by hydrogen sulphide, and gives no preciptate with calcium 
sulphate or ammonium oxalate, and with barium chloride no precipitate 
not entirely soluble in nitric acid. It should not attract moisture from 



CITRIC ACID. 291 

the air, should be entirely soluble in alcohol, and should be entirely 
consumed when heated to redness as platinum foil. 

The ordinary tartaric acid crystallizes in large prisms; very soluble in 
water and in alcohol, insoluble in ether; permanent in air; acid in taste 
and reaction. Its solutions become mouldy on standing. 

It fuses at 170°; at 180° it loses water and is gradually converted into 
an anhydride; at 200° — 210° the acid is decomposed with formation of 
new volatile products, pyruvic and pyrotartaric acids/ at higher tempera- 
tures the decomposition is more complete, and results in the production 
of acetic acid, carbon dioxide and monoxide, water, hydrocarbons and 
charcoal; if still further heated in air, it burns with an odor of caramel. 
If kept in fusion for some time, two molecules of the acid unite, with 
loss of the constituents of a molecule of water, to form tartralic or ditar- 
tric acid, C 8 II 10 O n . 

Tartaric acid is attacked by oxidizing agents with formation of carbon 
dioxide, water, and, in some instances, formic and oxalic acids. Certain 
reducing agents convert it into malic and succinic acids. With fuming 
nitric acid it forms a dinitro-compound, which is very unstable, and which, 
when decomposed below 36°, yields tartaric acid. It forms a precipitate 
with lime-water, soluble in an excess of water; in not too dilute solution 
it forms a precipitate with potassium sulphate solution; it does not pre- 
cipitate with the salts of calcium. When heated with a solution of auric 
chloride it precipitates the gold in the metallic form. 

As its formula indicates (see above), tartaric acid is tetratomic and 
dibasic; it forms many salts which are of medical importance, and ex- 
hibits a great tendency to the formation of double salts, such as tartar 
emetic (q. v.). 

When taken into the economy, as it constantly is in the form of tar- 
trates, the greater part is oxidized to carbonic acid (carbonates); but, if 
taken in sufficient quantity, a portion is excreted unchanged in the urine 
and perspiration. The free acid is poisonous in large doses. 

In pharmacy tartaric acid is used chiefly in effervescent mixtures, 
seidlitz powder, etc., and is frequently used in place of the more costly 
citric acid. In the arts it is extensively consumed in processes of dyeing. 

There exist anhydrides, ethers, and amides corresponding to the tar- 
taric acids, none of which is of medical interest. 



Citric Acid, C 6 H 8 0, + Aq, 

is best considered in this place, although its constitution is different from 
that of tartaric acid. . It exists in the acid juices of many fruits — lemon, 
strawberry, gooseberry, cherry, orange, etc. 

It is obtained from lemon-juice, which is filtered, boiled, and saturated 
with chalk. The insoluble calcium citrate is separated and decomposed 
with sulphuric acid, the solution filtered, and evaporated to crystallization. 

It crystallizes in large, right rhombic prisms, which lose their aq. at 
100°; very soluble in water, less soluble in alcohol, sparingly soluble in 
ether; heated to 100° it fuses; at 175° it is decomposed, with loss of water 
and formation of aconitic acid, C H 6 O 6 ; at a higher temperature, car- 
bon dioxide is given off, and itaconic acid, C 6 H e 4 , and citraconic acid, 
C B H 6 4 , are formed. 

Concentrated sulphuric acid decomposes it with evolution of carbon 



292 GENERAL MEDICAL CHEMISTRY. 

monoxide; oxidizing agents convert it into formic acid and carbon dioxide; 
or into carbon dioxide and acetone; or into oxalic and acetic acids and 
carbon dioxide. It is tetratomic and tribasic. 



PENTATOMIO ALCOHOLS. 

Only two of these compounds are known, and require mere mention. 

Quereite, C 6 H 12 5 — a sugar-like substance obtained from acorns. It 
forms hard crystals, soluble in water and in hot aqueous alcohol ; perma- 
nent in air; fuses at a temperature above 235°, and sublimes with a slight 
darkening in color. It is not affected by the alkalies; does not reduce 
Fehling's solution, and is not fermentable ; with a mixture of nitric and 
sulphuric acids it yields a detonating nitro-compound. 

Pinite is an isomere of quercite, obtained from the exudations of Cali- 
fornia pine (Pinus Lambertiand). It crystallizes in hard, white, mam- 
ellated' masses; very soluble in water, almost insoluble in alcohol and 
ether; its solution is dextrogyrous, [a] D =-f58.6°; it fuses without de- 
composition at 150°. It reduces solutions of silver nitrate, but not Feh- 
ling's solution; nor is it capable of fermentation. 



FOURTH SERIES OF HYDROCARBONS. 

Series C n IIj n _ 4 . 

But one of the lower terms of this series is known; this is valylene, 
C 5 H 6 , obtained by the action of an alcoholic solution of potash on valery- 
lene dibromide. It is a liquid, boiling at 45°. 

Among the higher terms of the series are many substances of industrial 
and medical importance. 

Terebenthene, C in H 16 , is the type of a great number of isomeric 
substances existing in the volatile oils or essences. It is the chief con- 
stituent of oil of turpentine. 

To obtain it in a state of purity, oil of turpentine is mixed with an 
alkaline carbonate, and distilled in vacuo over a water-bath, or by frac- 
tional distillation of the crude oil, those portions being collected which 
pass over at about 156°. 

Pure terebenthene is a colorless, mobile liquid; has the peculiar odor 
of turpentine; boils at about 156°; burns with a smoky, luminous flame; 
obtained from the turpentine of pinus maritima, it is lsevogyrous, puri- 
fied by distillation in vacuo, [a] D =: — 42.36°, by fractional distillation, 
a] D = — 40.32°; that obtained from pinus australis is dextrogyrous, 
V| D = 4-18.9°; specific gravity at 0° = 0.8767. 

It absorbs oxygen rapidly from the air, whether pure or in the com- 
mercial essence, becoming thick and finally gummy. Oxidizing agents, 
such as nitric acid, attack it energetically, causing it to ignite and burn 
suddenly, with separation of a large volume of carbon. Hydrochloric acid 
unites with it to form a number of compounds, as do also hydriodic and 
hydrobromic acids — all the compounds having the odor of camphor. 
When mixed with nitric acid diluted with alcohol and exposed to the air, 
it forms a crystalline pseudo-glycol, terpine. Chlorine, bromine, and iodine 
form compounds of substitution or of addition. 



FOURTH SERIES OF HYDROCARBONS. 293 

Turpentine — Terebenthina (U. S.) — is the name given to the concrete 
juice of various species of trees of the genera Pinus, Abies, and Larix, 
which consists of terebenthene, its isomeres, and resinous and other sub- 
stances. The product differs in composition and properties according 
to the kind of tree from which it is produced; the varieties recognized 
by the United States Dispensatory are the following: 

First. — White turpentine — Common American turpentine — obtained 
in North Carolina and adjacent States, from Pinus palustris and .P. tceda. 
It is yellowish white, semi-fluid at summer temperature, hard and solid 
when cooled; on exposure to air it becomes dry, hard, and brittle. It is 
usually subjected to distillation near the place of its collection, by which 
process it is separated into the volatile oil, or essence of turpentine (q. v.), 
and resin, or colophony (q. v.). 

Second. — European turpentine — Bordeaux turpentine — obtained in 
the south of France, etc., from P. sylvestris and P. maritima, is the va- 
riety principally used in Europe, but rarely finds its way to this country. 

Third. — Canada turpentine — Canada balsam — Balsam of fir — is pro- 
duced in Canada and Maine from abies balsamea. It is a tenacious semi- 
solid, of the consistency of honey when fresh, colorless or yellowish, sticky, 
bitter in taste, and having a balsamic odor; when long exposed to the air, 
or when heated over the water-bath, its volatile constituents are lost, and 
it is converted into a hard, brittle mass. 

Fourth. — Venice turpentine — produced principally in Switzerland from 
larix Furopoea. It is a thick, viscid liquid, yellowish or greenish in 
color; soluble in alcohol; does not concrete as readily as other turpentines. 

Fifth. — Chian turpentine is the product oi pistachio, terebinthus, grow- 
ing in the island of Chio, in the iEgean. It is a thick, greenish yellow 
liquid. 

Essence of turpentine — Oil of turpentine — Spirits of turpentine — Oleum 
terebinthinos (U. S., Br.) — is the volatile product of the distillation of tur- 
pentine. It is not identical with terebenthene, although that substance 
is its main constituent; it contains also hydrocarbons isomeric with tur- 
pentine and substances containing oxygen, which either pre-exist in the 
turpentine, or, more usually, result from the method of preparing the oil. 
When recently distilled, it is a colorless, limpid, neutral liquid; sp. gr. 
0.86; usually laevogyrous, sometimes dextrogyrous; when exposed to the 
air it rapidly becomes yellow and viscid. The action of reagents upon it 
is practically the same as upon terebenthene. 

The number of isomerides existing in oil of turpentine is very great; 
some are optically active, others inactive; they also vary in their specific 
gravities, fusing- or boiling-points, and capacity for absorbing oxygen; 
prominent among them are: 

Specific grav- Fusing- Boiling- 

ity at 60°. point. point. 

Isoterebenthene 0.8116 . . 177° 

Terebene 0.8266 . . 156° 

Terebenthene 0.8271 . . 156.5 9 

Camphenes 0.8738 45° 160° 

Action on the economy. — Oil of turpentine is used medicinally as a stim- 
ulant and diuretic; in large doses it acts as a narcotic-irritant poison. It 
is eliminated in the form of sulphoconjugated (?) acids with the urine, to 
which it communicates an odor of violets. 



294 GENERAL MEDICAL CHEMISTRY. 

Isomeres of Terebenthene. 

Essences. 

There exist a great number of bodies, the products of distillation of 
vegetable substances, which are known as essences, essential oils, volatile 
oils, distilled oils, or Olea distillata (U. S.). They resemble each other 
in being odorous, oily, sparingly soluble in water, more or less soluble in 
alcohol and ether; colorless or yellowish, inflammable, and prone to be- 
come resinous on exposure to air. They are not simple chemical com- 
pounds, but mixtures in which some constituent predominates, and in many 
of them the principal ingredient is a hydrocarbon, isomeric with tereben- 
thene, and consequently having the composition n C 10 H 16 ; the number of 
such isomeres is very great. Some contain hydrocarbons, others alde- 
hydes, acetones, phenols, and ethers. 

Of the numerous other hydrocarbons closely related to terebenthene, 
but two require further consideration as being the principal constituents 
of caoutchouc and gutta-percha, both of which are isomeric with tere- 
benthene. 

Caoutchouc — India-rubber — is a peculiar substance existing in sus- 
pension in the milky juice of quite a number of trees growing in warm 
climates. It is, when pure, a mixture of two hydrocarbons — caoutchene, 
CjoHje* and isoprene, C fi H 8 . 

The commercial article is yellowish brown; sp. gr. 0.919 to 0.942; soft, 
flexible; almost impermeable, but still capable of acting as a dialyzing- 
membrane when used in sufficiently thin layers. It is insoluble in water 
and alcohol, both of which, however, it absorbs by long immersion, the 
former to the extent of twenty-five per cent, and the latter of twenty per 
cent, of its own weight; it is soluble in ether, carbon disulphide, petro- 
leum, fatty and essential oils; its best solvent is carbon disulphide, either 
alone, or, better, mixed with five parts of absolute alcohol. 

It is not acted upon by dilute mineral acids, but is attacked by con- 
centrated nitric and sulphuric acids, and especially by a mixture of the 
two. Alkalies tend to render it tougher, although a solution of soda of 
40° B. renders it soft after an immersion of a few hours. Chlorine at- 
tacks it after a time, depriving it of its elasticity, and rendering it hard 
and brittle. When heated it becomes viscous at 145°, and fuses at 170°— 
180° to a thick liquid, which, on cooling, remains sticky and only regains 
its primitive character after a very long time; on contact with flame it 
ignites, burning with a reddish and very smoky flame, which is ex- 
tinguished with difficultv. 

The most valuable property of india-rubber, apart from its elasticity, 
is that which it possesses of entering into combination with sulphur to 
form what is known as vulcanized rubber, which is produced (the details 
of the process vary) by heating together the normal caoutchouc and sul- 
phur to 130° — 150°. Ordinary vulcanized rubber differs materially from 
the natural gum in its properties; its elasticity and flexibility are much 
increased; it does not harden when exposed to cold; it only fuses at 
200°; finally, it resists the action of reagents, of solvents, and of the at- 
mosphere much better than does the natural gum. 

Frequently rubber tubing is too heavily charged with sulphur for cer- 
tain chemical uses, in which case it may be desulphurized by boiling with 
dilute caustic soda solution. 



CAMPHORS. 295 

Sard rubber, vulcanite, or ebonite, is a hard, tough variety of vulcan- 
ized rubber, susceptible of a good polish, and a non-conductor of elec- 
tricity; used in the manufacture of a great many objects. It contains 
twenty to thirty-five per cent, of sulphur (the ordinary vulcanized rubber 
contains seven to ten per cent.), and is prepared by a process which re- 
quires great care and experience. 

Gutta-percha is the concrete juice of isonandra gutta. It is a tough, 
inelastic, brownish substance, having an odor similar to that of caout- 
chouc; at ordinary temperatures it is rather hard, but when heated to 
below the boiling-point of water it becomes soft and may be moulded, 
or even cast, so as to assume any form, which it retains on cooling; it 
may be welded with great facility at slightly elevated temperatures, is a 
good insulating and waterproofing material, and is sufficiently tough and 
pliable for use for belting for machinery. It is insoluble in water, alka- 
line solutions, dilute acids, including hydrofluoric, and in fatty oils; it is 
soluble in benzene, oil of turpentine, essential oils, chloroform, and es- 
pecially in carbon disulphide. A solution in chloroform is officinal as 
Liq. gutta perchoe (U. S.), and is used to obtain, by its evaporation, a 
thin film of gutta percha over parts which it is desired to protect from 
the air. It is attacked by nitric and sulphuric acids. 

When exposed to air and light, it is gradually changed from the sur- 
face inward, assuming a sharp acid odor, becoming hard and cracked, 
and even a conductor of electricity, thus losing, after a time, those char- 
acters w r hich render it valuable in the arts. 

Gutta-percha is a more complex substance than caoutchouc, and seems 
to be made up of three substances: Gutta, C 20 H 32 , seventy-five to eighty- 
two per cent., a white, tough substance, fusing at 150°, soluble in the 
ordinary solvents of gutta-percha, but insoluble in alcohol and ether. 
Albane, fourteen to nineteen per cent., a white, crystalline resin, heavier 
than water, fusible at 160°; soluble in benzine, essence of turpentine, 
carbon disulphide, ether, chloroform, and hot absolute alcohol; not at- 
tacked by hydrochloric acid; its composition is C 20 H 32 O 2 . Fluviale, four 
to six per cent., C 20 H 32 O, a yellowish resin, slightly heavier than water, 
hard and brittle at 0°, soft at 50°, liquid at 100°; soluble in the solvents 
of gutta-percha. 

Camphors and Resins. 

Most of the essential oils yield on distillation two products of differ- 
ent boiling-points; one of these is a hydrocarbon, in most instances of 
the terebenthene series, liquid at ordinary temperatures, and sometimes 
known as an eleoptene. The other, of higher boiling-point, and solid at 
ordinary temperatures, designated a stearoptene, is an oxidized product, 
and either exists as such in the vegetable exudation, or is produced 
during subsequent treatment. 

Camphors. 

These stearoptenes are probably aldehydes or alcohols corresponding 
to hydrocarbons related to terebenthene; their composition is clearly de- 
termined, although their constitution is as yet uncertain. 

They are quite numerous, and many of the varieties occur in several 
different modifications; the most important are: 

Common Camphor — Japan camphor — Laurel camphor — Cam- 



296 GENERAL MEDICAL CHEMISTRY. 

pholic aldehyde — Camphora (U '. S., Br.) — C 10 H 16 O. — There exist at least 
three modifications of this substance, which differ from each other, ap- 
parently, only in the sources whence they are obtained and in their 
action upon polarized light; they are: 

First. — JDextrocamphor, or laurel camphor, obtained from laurus cam- 
phora— Camphore qfficinarum — [a] D =+47.i°. 

Second. — Loevocamphor, obtained from matricaria postlanium — [a] 
D =— 47.4°. 

Third. — Inactive camphor, obtained from the essential oils of rose- 
mary, sage, lavender, and origanum, is without action upon polarized light. 

The only one of these which is of practical importance is the first, 
which is the ordinary camphor of the shops. 

It occurs as a white, translucent, crystalline solid ; sp. gr. 0.986 — 
0.996; of a hot, bitter taste, and a well-known aromatic odor, sparingly 
soluble in water, to which it communicates its odor. When a small piece 
is thrown upon water, it takes on a rapid, gyratory motion over the sur- 
face, which is instantly stopped when a drop of essential oil is allowed to 
fall on the water. It is quite soluble in ether, acetic acid, methyl alcohol, 
carbon disulphide, the oils, and alcohol. The spir. camphorce is an alco- 
holic solution of two ounces to the pint. It fuses at 175° and boils at 
204°. It is volatile at all temperatures, and is readily sublimed. 

It ignites readily, and burns with a luminous flame. Cold nitric acid 
dissolves it, and from the solution it is precipitated unchanged by water. 
Boiling nitric acid or potassium permanganate solution oxidize it to dex- 
trocamphoric acid, C 10 H 16 O 4 . Concentrated sulphuric acid forms with it a 
black solution, from which water precipitates an oily material called cam- 
phrene. Distilled with phosphoric anhydride, it yields cymene, C 10 H 14 . 
Alkaline solutions, by long heating under pressure, convert it into cam- 
phic acid, C 10 H 16 O 2 , and borneol. Chlorine attacks it with difficulty. 
Bromine unites with it to form an unstable compound, which forms ruby- 
red crystals having the composition C 10 H 66 OBr 2 . These crystals, when 
heated to 80° — 90°, fuse and give off hydrobromic acid, there remain- 
ing an amber-colored liquid, which solidifies on cooling and yields, by 
recrystallization from boiling alcohol, long, hard, rectangular prisms, in- 
soluble in water, soluble in alcohol, ether, chloroform, and oils ; this is 
the monobromo-camphor, recently introduced as a therapeutic agent. 
When the vapor of camphor is passed over a mixture of fused potash and 
lime heated to 300° — 400°, it unites directly with the potash to form the 
potassium salt of campholic acid, C 10 H l8 O 2 . 

Camphor is largely used in the household as a destroyer of moths, and 
in medicine as an antispasmodic ; in overdoses it acts as a poison, the 
cases, however, usually terminating in recovery. It is said to be a valu- 
able antidote in strychnine-poisoning. 

Borneol — Borneo camphor — Camphol — Camphyl alcohol — C I0 H 16 O 
— is usually obtained from dryobalanops camphora, although it may be 
obtained from other plants, and even artificially by the hydrogenation of 
laurel Camphor. The product from these different sources is the same 
chemically, so far as we can determine, but varies, like the modifications 
of camphor, in its action on polarized light; thus the specific rotary power 
is of 



Borneol from amber, 
Borneol from dryobalanops, 
Borneol from madder, 



Borneol artificial, [a] D =H-44.9 



«]d=+ 4.1 
a] D =+33.4 
aj D =— 33.4 



RESINS. 297 

It forms small, white, transparent, friable crystals; has an odor which 
recalls at the same time those of laurel camphor and of pepper; has a hot 
taste ; is insoluble in water, readily soluble in alcohol, ether, and acetic 
acid ; fuses at 198°, boils at 212°. 

It is a true alcohol, and enters into double decomposition with acids to 
form ethers. When heated with phosphoric anhydride, it yields a hydro- 
carbon, borneene, C 10 H 16 . Oxidized by nitric acid, it is converted into laurel 
camphor. 

This substance is very rarely exported from the countries in which it 
is produced. 

Menthol — Menthyl alcohol — C 10 H 20 O — is a camphor existing in essen- 
tial oil of peppermint. It crystallizes in colorless prisms; fusible at 36°; 
boiling at 210°; sparingly soluble in water; readily soluble in alcohol, 
ether, carbon disulphide, and in acids. Corresponding to it are a series 
of menthyl ethers. 

Eucalyptol, C 12 H 20 O — is contained in the leaves of eucalyptus globulus; 
it is liquid at ordinary temperatures, and boils at 175°; by distillation with 
phosphoric anhydride it yields eucalyptene, C 12 H 18 . 

Terpine — Terebenthene bihydrate — C :0 H 16 ,2H 2 O + Aq — is sometimes 
spontaneously deposited from oil of turpentine containing water; it may 
be obtained by frequently agitating for a month or more a mixture of oil 
of turpentine, alcohol, and ordinary nitric acid. It forms fine, large, rhom- 
bic prisms; sp. gr. 1.0994; sparingly soluble in cold water; soluble in hot 
water, alcohol, and ether; fusible at 103°. 

Terpinol, (C 10 H 16 ) 2 H 2 O — is formed when terpine in solution in warm 
water is treated with a very small quantity of sulphuric or of hydrochloric 
acid, and distilling. It is a colorless liquid; has an odor of hyacinth; sp. 
gr. 0.852; boils at 168°, at which temperature it suffers partial decompo- 
sition. It appears to possess the function of an ether. 

Resins. 

Notwithstanding the wide diffusion and industrial importance of these 
substances, and owing to the uncertainty still existing as to their chem- 
ical nature, it is difficult to define precisely what is meant by a resin. 

They are generally the products of oxidation of the hydrocarbons allied 
to terebenthene; are amorphous (rarely crystalline); insoluble in water; 
soluble in alcohol, ether, and essences. Many of them contain acids. 

They may be divided into several groups, according to the nature of 
their constituents: 1st, Balsams, which are usually soft or liquid, and are 
distinguished by containing free cinnamic or benzoic acid (q. v.). The 
principal members of this group are benzoin, liquidambar, Peru balsam, 
styrax, and balsam tolu. 2d. Oleo-resins consist of a true resin mixed 
with an oil, and usually with an oxidized product other than cinnamic 
or benzoic acid. The principal members of this group are Burgundy and 
Canada pitch, Mecca balsam, and the resins of capsicum, copaiva, cubebs, 
elemi, labdanum, and lupulin. 3d. Gum-resins are mixtures of true re- 
sins and gums. Many of them are possessed of medicinal qualities, aloes, 
ammoniac, asafoetida, bdellium, euphorbium, galbanum, gamboge, guaiac, 
myrrh, olibanum, opoponax, and scammony. 4th. True resins are hard 
substances obtainable from the members of the three previous classes, and 
containing neither essences, gums, nor aromatic acids. Such are colophony 
or rosin, copal, dammar, dragon's blood, jalap, lac, mastic, and sandarac. 
5th. Fossil resins, such as amber, asphalt, and ozocerite. 



298 GENERAL MEDICAL CHEMISTRY. 



HEXATOMIC ALCOHOLS. 

There exist, so far as at present known, but two alcohols of this series, 
isomeres of each other. They may be regarded as the hydrates of a hy- 
drocarbon of the terebenthene series, fl H e , which is only known in com- 
bination. They are mannite and dulcite. 

Mannite — Fraxine — Mannityl hydrate — Mannitic alcohol — C 6 H 8 
(OH) 6 — was first obtained from manna, of which it forms sixty to eighty 
per cent. It exists also in a great number of vegetables, and in cider 
and wine, being formed as one of the products of viscous fermentation. 
It has also been obtained by partial synthesis, by the action of nascent 
hydrogen on inverted cane- and milk-sugar. It is best prepared from 
manna by extraction with boiling alcohol, recrystallization, and decolor- 
ization if necessary. 

It crystallizes in silky prisms, usually arranged in radiating bundles. 
It is sweetish in taste; fermentable with difficulty; without action on polar- 
ized light; soluble in water and alcohol; insoluble in ether; fusible at 
160°; it boils at 200°. 

When heated to 100° with hydrochloric acid for some time, it is con- 
verted into mannitan, C^H^O,.. With the acids generally it combines, 
with elimination of water, to form mannitic ethers; it also dissolves in al- 
kaline solutions. It is not capable of reducing the cupropotassic solu- 
tions, either hot or cold. Nitric acid oxidizes it to saccharic acid (q. v.), 
and ultimately to oxalic acid. By the action of moist platinum-black a 
portion is converted into ma?initic acid, C 6 H 12 7 , and a portion into ma?i- 
nitose, 6 H l2 O 6 . 

Dulcite — Melampyrine — Dulcose — C 6 H 14 6 — the isomere of mannite, 
is obtained from a Madagascar plant of the genus melampyrum. It re- 
sembles mannite closely in its properties and reactions, but differs from 
it in fusing at 182°, and in yielding, when oxidized by nitric acid, mucic 
in place of saccharic acid. 

Saccharic acid, C 4 H 4 (OH) 4 (COOH) 2 — is a dibasic acid produced 
by the oxidation of mannite, cane-sugar, and other kinds of sugar. It 
forms a non-crystalline, friable mass; deliquescent; soluble in water 'and 
alcohol; insoluble in ether; it is dextrogyrous when made from cane- 
sugar. It forms a series of salts and ethers called saccharates. 

IVEucic acid, C,H, O — is a dibasic acid, isomeric with saccharic 

» G 10 8 # ' 

acid, which it closely resembles. It is formed by the oxidation of dulcite, 
milk-sugar, or gum arabic, by nitric acid. 

It is a white, crystalline powder; very sparingly soluble in cold water, 
insoluble in alcohol. By long boiling with water it is converted into 
another isomere, paramucic acid, soluble in water and alcohol. Sulphuric 
acid dissolves it, the solution being red and containing a sulphoconjugate 
acid. Nitric acid by prolonged action oxidizes it to racemic and oxalic 
acids. When subjected to dry distillation it is decomposed into water, 
carbon dioxide, and pyromucic acid, C & H 4 3 . 

Corresponding to pyromucic acid is an aldehyde, called furfurol, or 
oil of bran, a colorless, highly aromatic oil, sp.gr. 1.17; boiling-point, 
162°; prepared by distilling bran, starch, sawdust, etc., with dilute sul- 
phuric acid. 



GLUCOSES. 



299 



CARBOHYDRATES. 

The substances classed under this head are composed of carbon, hy- 
drogen, and oxygen; they all contain six atoms of carbon or some multiple 
of that number, and the hydrogen and oxygen which they contain are 
always in the same proportion to each other as that in which they exist in 
water. Their precise constitution is, as yet, not definitely settled, 
although there are very strong grounds for believing that they are all deriv- 
atives of hexatomic alcohols, and that they are, some of them aldehyds, 
others alcohols, and others ethers. Most of them are important constitu- 
ents of animal or vegetable organisms, and but few of them have been 
hitherto produced artificially — none, so far as we know, by complete 
synthesis. 

They are divisible into three well-marked groups, the members of 
each of which are isomeric with each other, and have many important 
characters in common. These groups are the following: 



I. Glucoses. 

.(<W>.). 

•+■ Glucose. 
(Dextrose.) 

— Laevulose. 
Mannitose. 

-f Galactose. 
Inosite. 

— Sorbin. 
— Eucalin. 



II. Saccharoses. 
n(C 19 H 9a O n ). 

+ Saccharose. 
4- Lactose. 
+ Maltose. 
4- Melitose. 
+ Melezitose. 
+ Trehalose. 
+ My cose. 

Synanthrose. 
4- Parasaccharose. 



III. Amyloses. 
.(0.H..OJ. 

4- Starch. 
4- Glycogen. 
4- Dextrin. 
— Inulin. 

Tunicin. 

Cellulose. 

Gums. 



Glucoses, 6 H 12 O fl . 

Glucose — Grape-sugar — Dextrose — Liver-sugar — Diabetic sugar. — 
The substance from which this group takes its name is widely diffused 
in nature. It exists, accompanied by laevulose, or saccharose, in all 
sweet and acidulous fruits; in many vegetable juices; in honey; in the 
animal economy in the contents of the intestines, in the liver, bile, 
thymus, heart, lungs, blood, and in small quantity in the urine. Patho- 
logically it is found in the saliva, perspiration, faeces, and enormously 
increased in the blood and urine in diabetes mellitus (see below). It 
may also be obtained by decomposition of certain vegetable substances 
called glucosides (q. v.). 

It can be, and is, in the arts, prepared artificially by heating starch or 
cellulose for twenty-four to thirty-six hours with a dilute mineral acid 
(sulphuric). Glucose obtained by this method is very largely used, both 
legitimately and fraudulently; it is, however, liable to contamination with 
traces of arsenic, which it receives from the sulphuric acid. Starch is 
also converted into glucose by the influence of a peculiar ferment, dias- 
tase, formed during the germination of grain. 

Glucose crystallizes with difficulty from its aqueous solution in white, 
opaque, spheroidal masses containing 1 aq. ; from alcohol in fine, trans- 
parent, anhydrous prisms; at about 60 degrees in dry air the hydrated 



300 GENERAL MEDICAL CHEMISTRY. 

glucose loses its water. It is soluble in all proportions in hot water; 
in one-third part of cold water (less soluble than cane-sugar) ; soluble in 
alcohol. It is less sweet in taste than cane-sugar, two and one-half parts 
of glucose being required to produce the same sweetening as one part of 
saccharose. Solutions of glucose are dextrogyrous [«] D = +57.6°. When 
heated to 170° it loses water, and is converted into glucosan, C 6 H 10 6 . 

When heated with the diluted mineral acids, glucose is decomposed, 
yielding a brown substance, ulmic acid, and, in the presence of air, formic 
acid. It dissolves in concentrated sulphuric acid without coloration, 
forming sulphoglucic acid. Cold, concentrated nitric acid converts it into 
nitro- glucose y hot dilute nitric acid oxidizes and decomposes it to a mix- 
ture of oxalic and oxysaccharic acids. With the organic acids it forms a 
number of ethers. 

Solutions of glucose dissolve potash, soda, lime, baryta, and the oxides 
of lead and copper, with which it forms well-defined compounds, which 
are, however, very prone to decomposition. When glucose solution is 
heated with an alkali, it turns brown (yellow if the quantity of glucose be 
small), and assumes a peculiar, molasses-like odor; this change is due to 
the formation of melassic and glucic acids (see below). 

Glucose precipitates silver from solutions of its salts, and in the pres- 
ence of free ammonia the metal adheres to the sides of the glass vessel as 
a brilliant mirror. When an alkaline solution of a cupric salt is heated 
in the presence of glucose, the sugar reduces the copper salt and precipi- 
tates cuprous oxide (see below). Mercury is precipitated from an alka- 
line solution of mercuric cyanide, when heated with glucose. It forms 
definite, crystalline compounds with sodium chloride. Sodium amalgam 
converts glucose in aqueous solution into mannite. Subnitrate of bis- 
muth, suspended in a hot solution of glucose, containing sodium car- 
bonate, turns black or brown from its reduction to bismuth. In the 
presence of yeast it is converted into alcohol and carbon dioxide, by 
fermentation (see pp. 170, 303); in the presence of sour milk or of cheese, 
it enters into lactic fermentation. 

If a solution of glucose be rendered faintly blue with indigo solution, 
then faintly alkaline with sodium carbonate solution, and heated to near 
boiling without agitation, the color changes to violet and then to yellow. 
The blue color is restored by agitation. 

Physiological. — The greater part of the glucose in the economy in 
health is introduced with the food, either in its own form or as other car- 
bohydrates, which by digestion are converted into glucose ; a certain 
quantity is also produced in the liver at the expense of glycogen, a for- 
mation which continues for some time after death. In some forms of 
diabetes the production of glucose in the liver is undoubtedly greatly 
increased. The quantity of sugar normally exsisting in the blood varies 
from 0.81 to 1.231 part per thousand; in diabetes it rises as high as 5.8 
parts per thousand. 

Under normal conditions and with food not too rich in starch and 
saccharine materials, the quantity of sugar eliminated as such is exceed- 
ingly small — so small indeed that some observers have contested the fact 
of any being eliminated in health. It is oxidized in the body, and the 
ultimate products of such oxidation eliminated as carbon dioxide and 
water. Whether or no intermediate products are formed, is still uncer- 
tain; the probability, however, is that there are. The oxidation of sugar 
is impeded in diabetes. Where this oxidation, or any of its steps, occurs, 
is at present a matter of conjecture merely; if, as is usually believed, 



GLUCOSES. 301 

glucose disappears to a marked extent in the passage of the blood through 
the lungs, the fact is a strong support of the view that its transformation 
into carbon dioxide and water does not occur as a simple oxidation, as the 
notion that sugar or any other substance is " burned " in the lung, beyond 
the small amount required by the nutrition of the organ itself, is scarcely 
tenable at the present day. 

So long as the quantity of glucose in the blood remains at or below 
the normal percentage, it is not eliminated in the urine in quantities 
appreciable by the tests usually employed; when, however, the amount 
of glucose in the blood surpasses this limit from any cause, the urine 
becomes saccharine, and that to an extent proportional to the increase of 
glucose in the circulating fluids. The causes which may bring about such 
an increase are numerous and varied; many of them are entirely consistent 
with health, and the mere presence of increased quantities of sugar in the 
urine is no proof, taken by itself, of the existence of diabetes. Sugar is 
detectable by the ordinary tests in the urine under the following circum- 
stances: Physiologically . — 1st, in the urine of pregnant women and dur- 
ing lactation; it appears in the latter stages of gestation and does not 
disappear entirely until the suppression of the lacteal secretion. 2d, in 
small quantities in sucking children from eight days to two and one-half 
months. 3d, in the urine of old persons (seventy to eighty years). 4th, 
in those whose food contains a large amount of starchy or saccharine 
material; to this cause is due the apparent prevalence of diabetes in certain 
localities, as in districts where the different varieties of sugar are pro- 
duced. Pathologically. — 1st, in abnormally stout persons, especially in 
old persons and in women at the period of the menopause; the quantity 
does not exceed eight to twelve grams per 1,000 c.c.,and disappears when 
starchy and saccharine food is withheld; this form of glycosuria is very 
liable to develop into true diabetes when it appears in young persons. 
2d, in diseases attended with an interference with the respiratory pro- 
cesses — lung diseases, etc. 3d, in diseases in which there is interference 
with the hepatic circulation — hepatic congestion, compression of the portal 
vein by biliary calculi, cirrhosis, atrophy, fatty degeneration, etc. 4th, in 
many cerebral and cerebro-spinal disturbances — general paresis, dementia, 
epilepsy; by puncture of the fourth ventricle. 5th, in intermittent and 
typhus fevers. 6th, by the action of many poisons — carbon monoxide, 
arsenic, chloroform, curari; by injection into an artery of ether, ammo- 
nia, phosphoric acid, sodium chloride, amyl nitrite, glycogen. 7th, in 
true diabetes the elimination of sugar in the urine is constant, unless 
arrested by suitable regulation of diet, and not temporary, as in the con- 
ditions previously mentioned. The quantity of urine is increased, some- 
times enormously, and it is of high specific gravity. The elimination of 
urea is increased absolutely, although the quantity in 1,000 c.c. may be 
less than that normally existing in that bulk of urine. The quantity of 
sugar in diabetic urine is sometimes enormous; an elimination of 200 grams 
in twenty-four hours is by no means uncommon; instances in which the 
amount has reached 400 to 600 grams are recorded, and one case in which 
no less than 1,376 grams were discharged in one day. The elimination is 
not the same at all hours of the day; during the night less sugar is voided 
than during the day; the hourly elimination increases after meals, reach- 
ing its maximum in four hours, after which it diminishes to reach the 
minimum in six to seven hours, when it may disappear entirely ; this 
variation is more pronounced the more copious the meal. It is obvious 
from the above, that, in order that quantitative determinations of sugar in 



302 



GENERAL MEDICAL CHEMISTRY. 



urine shall be of clinical value, it is necessary that the determination be 
made in a sample taken from the mixed urine of twent\'-four hours. 

The relation existing between the quantity of sugar in the blood and 
its elimination by the urine in diabetes is well shown by the following re- 
sults of Pavy, which also show the beneficial effects of restricting the diet: 





TJbink. 


Blood. 




Quantityin 
24 hours. 


Specific 
gravity. 

1040 
1041 
1031 
1036 
1033 
1036 

1034 


Sugar excreted 
in 24 hours. 


Sugar in 
1.000 parts. 

109.91 
94.08 
61.34 
93.39 
45.49 
48.11 

31.76 


Sugar in 
1,000 parts. 


Case I. Mixed diet 


6608 c.c. 
6474 c.c. 
3407 c.c. 
5878 c.c. 
2470 c.c. 
1704 c.c. 

852 c.c. 


751.6 grams. 
633.0 grams. 
245.2 grams. 

567.7 grams. 

115.8 grams. 
21.81 grams. 

14.40 grams. 


5.763 


Case II. Mixed diet 


5.545 


Case II. Restricted diet 


2.625 


Case III. Mixed diet. . , 


4.970 


Case III. Restricted diet 


2.789 


Case IV. Partly restricted diet . . 
Case IV. Partly restricted diet, ) 
3£ months later. . . . ) 


1.848 
1.543 



Tests for the presence of glucose. — A saccharine urine is usually abun- 
dant in quantity, pale in color, of high specific gravity, covered with a 
persistent froth on being shaken, and exhales a peculiar odor; when evap- 
orated it leaves a sticky residue. The presence of glucose in urine is 
indicated by the following tests: 

If the urine be albuminous, it is indispensable that the albumen be 
separated before any of the tests for sugar are applied; this is done by 
adding one or two drops of acetic acid, or, if the urine be alkaline, just 
enough acetic acid to turn the reaction to acid, and no more, heating 
over the water-bath until the albumen has separated in flocks, and 
filtering. 

First. — When examined by the polarimeter (see p. 303) it deviates 
the plane of polarization to the right. 

Second. — When mixed w T ith an equal volume of liquor potassae and 
heated, it turns yellow, and, if sugar be abundant, brown; a molasses-like 
odor is at the same time observable (Moore's test). 

Third. — The urine, rendered faintly blue with indigo solution and 
faintly alkaline with sodium carbonate, and heated to boiling without 
agitation, turns violet and then yellow if sugar be present; on agitation 
the blue color is restored (Mulder-Neubauer test). 

Fourth. — About 1 c.c. of the urine, diluted with twice its bulk of water, 
is treated with two or three drops of cupric sulphate solution and about 
1 c.c. of caustic potassa solution; if sugar be present the bluish precipi- 
tate is dissolved on agitation, forming a blue solution; the clear blue fluid, 
when heated to near boiling, deposits a yellow, orange, or red precipitate 
of cuprous oxide if sugar be present (Trommer's test). In the applica- 
tion of this test an excess of cupric sulphate is to be avoided, lest the 
color be masked by the formation of the black cupric oxide. Sometimes 
no precipitate is formed, but the liquid changes in color from blue to 
yellow; this occurs in the presence of small quantities of cupric salt and 
large quantities of sugar, the cuprous oxide being held in solution by the 
excess of glucose; in this case the test is to be repeated, using a sample 
of urine more diluted with water. In some instances, also, the reaction 
is interfered with by excess of normal constituents of the urine, uric acid, 
creatinine, coloring matter, etc., and, instead of a bright precipitate, a 



GLUCOSES. 303 

muddy deposit is formed; when this occurs the urine is heated with ani- 
mal charcoal, and filtered; the filtrate evaporated to dryness; the residue 
extracted with alcohol; the alcoholic extract evaporated; the residue 
redissolved in water, and tested as described above. 

Fifth. — Four or five cubic centimetres of Fehling's solution (see p. 
304) are heated in a test-tube to boiling; it should remain unaltered; the 
urine is then added guttatim; if it contain sugar, the mixture turns green 
and a yellow or red precipitate of cuprous oxide is formed, usually darker 
in color than that obtained by Trommer's test. The absence of glucose 
is not to be inferred until a bulk of urine equal to that of the Fehling's 
solution used has been added, and, the mixture boiled from time to time 
without the formation of a precipitate. This test is certainly the most 
convenient and the most reliable for clinical purposes. 

Sixth. — A few cubic centimetres of the urine are mixed in a test-tube 
with an equal volume of solution of sodium carbonate (one part crystal, 
carbonate and three parts water), a few granules of bismuth subnitrate 
are added, and the mixture boiled for some time (until it begins to " bump," 
if necessary); if sugar be present, the bismuth powder turns brown or 
black by reduction to elementary bismuth (Boettger's test). No other 
normal constituent of the urine reacts with this test; a fallacy is, how- 
ever, possible from the presence of some compound, which, by giving up 
sulphur, may cause the formation of the black bismuth sulphide; to guard 
against this, when an affirmative result has been obtained, another sample 
of urine is rendered alkaline with caustic potassa solution and boiled with 
pulverized litharge; the powder should not turn black. 

Use may also be made in this test of an alkaline solution of bismuth, 
made by dissolving four grams of Rochelle salts in 100 grams of caustic 
potassa solution of sp. gr. 1.33, warming gently, and adding bismuth sub- 
nitrate as long as it dissolves (about two grams). A few drops of this so- 
lution are added to three or four cubic centimetres of the urine, which is 
then boiled. The reagent does not keep well. 

Seventh. — A solution of sugar, mixed with good yeast and kept at 25°, 
is decomposed into carbon dioxide and water. To apply the fermentation- 
test to urine, take three test-tubes, A, B, and C, place in each some washed 
(or compressed) yeast, fill A completely with the urine to be tested, and 
place it in an inverted position, the mouth below the surface of some of the 
same urine in another vessel (the entrance of air being prevented, during 
the inversion, by closing the opening of the tube with the finger, or a 
cork on the end of a wire, until it has been brought below the surface of 
the urine). Fill B completely with some urine to which glucose has been 
added, and C with distilled water, and invert them in the same way as 
A: B in saccharine urine, and C in distilled water. Leave all three 
tubes in a place where the temperature is about 25°, for twelve hours, 
and then examine them. If gas have collected in B over the surface of 
the liquid, and none in A, the urine is free from sugar; if gas has collected 
in both A and B, and not in C, the urine contains sugar; if no gas has 
collected in B, the yeast is worthless, and if any gas be found in C, the 
yeast itself has given off C0 2 ; in the last two cases the process must be 
repeated with a new sample of j^east. 

Quantitative determination of glucose. — First. — By the polar imeter. — 
The filtered urine is observed by the polariscope (see p. 31) and the mean 
of half a dozen readings taken as the angle of deviation; from this the 



a 



percentage of sugar is determined by the formula p=—— — -, in which 

I .v X I 



304 GENERAL MEDICAL CHEMISTRY. 

£>=the weight, in grams, of glucose in 1 c.c. of urine; a—the angle of 
deviation; /=the length of the tube in decimeters. The same formula 
may be used for other substances by substituting for 57.6 the value of 
[a] D for that substance. 

If the urine contain albumen, it must be removed, as it exerts an ac- 
tion on polarized light opposite to that of glucose. It is always prefer- 
able, if possible, to observe the urine without treatment for decoloriza- 
tion; if, however, it be too highly colored, some treatment becomes neces- 
sary. The use of animal charcoal for this purpose should be avoided, as 
it retains a considerable quantity of sugar; the best method is to add a 
known volume of lead subacetate and filter, account being- taken in the 
calculation of the dilution so caused. 

Second. — By specific gravity; Moberfs method. — The specific gravity 
of the urine is carefully determined at 25°; yeast is then added, and the 
mixture kept at 25° until fermentation is complete; the specific gravity is 
again observed, and will be found to be lower then before; each degree of 
diminution represents 0.2196 grams of sugar in 100 c.c. of urine. 

Neither first nor second gives strictly accurate results, even when care- 
fully conducted; the results are, however, sufficiently accurate for medical 
purposes. 

Third. — By Fehling's solution. — Of the many formulae for Fehling's 
solutions, the one to which we give the preference is that of Dr. Piffard. 
Two solutions are required: 

I. Cupric sulphate (pure, crystals) 51.98 grams. 

Water 500.0 c.'c. 

II. Rochelle salt (pure, crystals) 259.9 grams. 

Sodic hydrate solution, sp. gr. 1.12 1000.0 c.c. 

When required for use, one volume of No. I. is mixed with two vol- 
umes of No. II. The copper contained in 20 c.c. of this mixture is pre- 
cipitated as cuprous oxide by 0.1 gram glucose. 

To use the solution, 20 c.c. of the mixed solutions are placed in a flask 
of 250 — 300 c.c. capacity, 40 c.c. of distilled water are added, the whole 
thoroughly mixed and heated to boiling. On the other hand, the urine 
to be tested is diluted with four times its volume, if poor in sugar, and 
with nine times its volume if highly saccharine (the degree of dilution 
required is, with a little practice, readily determined by the appearance 
of the deposit obtained in the qualitative testing); the water and urine 
are thoroughly mixed and a burette filled with the mixture. A few drops 
of aqua ammonias are added to the Fehling's solution and the diluted 
urine added, in small portions toward the end, until the blue color is 
entirely discharged — the contents of the flask being made to boil briskly 
between each addition from the burette. When the liquid in the flask 
shows no blue color when looked through with a white background, 
the reading of the burette is taken; this reading, divided by five if the 
urine was diluted with four volumes of water, or by ten if with nine 
volumes, gives the number of cubic centimetres of urine containing 0.1 
gram of glucose; and consequently the elimination of glucose in 
twenty-four hours, in decigrams, is obtained by dividing the number of 
cubic centimetres of urine in twenty-four hours by the result obtained 
above. 



GLUCOSES. 305 

Example. — 20 c.c. Fehling's solution used, and urine diluted with four 

volumes of water. 

36 5 
Reading of burette: 36.5 c.c. — -^ — = 7.3 c.c. urine contain 0.1 gram 

glucose. Patient is passing 2,436 c.c. urine in twenty-four hours. 
o a *** r* 

— '—— — = 333.6 decigr. = 33.36 gram glucose in twenty-four hours. 
I .o 

The accuracy of the determination may be controlled by filtering off 
some of the fluid from the flask at the end of the reaction; a portion of 
the filtrate is acidulated with acetic acid and treated with potassium fer- 
rocyanide solution; if it turn reddish brown, the reduction has not been 
complete, and the result is affected with a plus error. To another portion 
of the filtrate a few drops of cupric sulphate solution are added and the 
mixture boiled; if any precipitation of cuprous oxide be observed, an ex- 
cess of urine has been added, and the result obtained is less than the 
true one. 

This method, when carefully conducted with accurately prepared and 
undeteriorated solutions, is the best adapted to clinical uses. The copper 
solution should be kept in the dark, in a well-closed bottle, and the stopper 
and neck of the No. II. solution should be well coated with paraffin. 

Fourth. — Gravimetric method. — When more accurate results than 
are obtainable by Fehling's volumetric process are desired, recourse must 
be had to a determination of the weight of cuprous oxide obtained by 
reduction. A small quantity of freshly prepared Fehling's solution is 
heated to boiling in a small flask; to it is gradually added, with the pre- 
cautions observed in the volumetric method, a known volume of urine, 
such that at the end of the reduction there shall remain an excess of un- 
reduced copper salt. The flask is now completely filled with boiling water, 
corked, and allowed to cool. The alkaline fluid is separated as rapidly 
as possible from the precipitated oxide by decantation and filtration 
through a small double filter, and the precipitate and flask repeatedly 
washed with hot water until the washings arc no longer alkaline: a small 
portion of the precipitate remains adhering to the walls of the flask. The 
iilter and its contents are dried and burned in a weighed porcelain cru- 
cible; when this has cooled, the flask is rinsed out with a small quantity 
of nitric acid; this is added to the contents of the crucible, evaporated 
over the water-bath, the crucible slowly heated to redness, cooled, and 
weighed : the difference between this last weight and that of the crucible -f- 
that of the filter-ash, is the weight of cupric oxide, of which 220 parts=100 
parts of glucose. 

Laevulose — Uncrystallizable sugar — forms the uncr} r stallizable por- 
tion of the sugar of fruits and of honey, in which it is associated with 
glucose; it is also produced artificially by the prolonged action of boil- 
ing water upon inulin, and as one of the constituents of inverted sugar 
(see p. 308). It may be separated from inverted sugar by adding calcic 
hydrate, expressing the soluble calcium-glucose compound, suspending 
the sparingly soluble lsevulose-calcium compound in water, decomposing 
with oxalic acid, and evaporating the solution. 

Lsevulose is not capable of crystallization, but may be obtained as a 
thick syrup ; very deliquescent and soluble in water, insoluble in absolute 
alcohol; it is sweeter but less readily fermentable than glucose, which it 
equals in the readiness with which it reduces cupro-potassic solutions. 
Its prominent physical propertv, and that to which it owes its name, is 
20 



306 GENERAL MEDICAL CHEMISTRY. 

its strong left-handed polarization, [«] D = — 106° at 15°. "When heated 
to 170°, it is converted into the solid, amorphous lazvulosan, C C H O . 

IVTannitose is obtained by the oxidation of mannite, whose aldehyde 
it probably is. It is a yellow, uncrystallizable sugar, having many of the 
characters of glucose, but being optically inactive. 

Galactose — sometimes improperly called lactose — is formed by the 
action of dilute acids upon lactose, milk-sugar, as glucose is formed from 
saccharose. It differs from glucose in crystallizing more readily, in being 
very sparingly soluble in cold alcohol, in its action upon polarized light, 
[«] D = + 83.33°, and in being oxidized to mucic acid by nitric acid. 

Inosite — Muscle-sugar — exists in the liquid of muscular tissue, in the 
lungs, kidneys, liver, spleen, brain, and blood; pathologically, in the 
urine in Bright's, diabetes, and after the use of drastics in urremia, and 
in the contents of hydatid cysts; also in the seeds and leaves of certain 
plants. What the source and function of inosite in the animal economy 
may be is still a matter of conjecture. 

It may be prepared from muscular tissue or from green beans; the 
latter are reduced to a pulp, boiled with water for half an hour, expressed, 
the liquid reduced to a syrup over the water-bath, treated with alcohol 
until a persistent deposit is formed, and set aside; crystalline crusts of 
inosite separate. 

It forms long, colorless, monoclinic crystals, containing two molecules 
of water of crystallization, usually arranged in groups having a cauliflower- 
like appearance. It effloresces in dry air; has a distinctly sweet taste; is 
easily soluble in water, difficultly in alcohol; insoluble in absolute alcohol 
and in ether; it is without action upon polarized light. 

The position of inosite in this series is based entirely upon its chem- 
ical composition, as it does not possess the other characteristics of the 
group. It does not enter directly into alcoholic fermentation, although 
upon contact with putrefying animal matters it produces lactic and butyric 
acids; when boiled with barium or potassium hydrate, it is not even col- 
ored; in the presence of inosite, potash precipitates with cupric sulphate 
solution, the precipitate being redissolved in an excess of potash; but no 
reduction takes place upon boiling the blue solution. 

The presence of inosite is indicated by the f ollowingreactions : Believer's. 
— Treated with nitric acid, the solution evaporated to near dryness, and 
the residue moistened with ammonium hydrate and calcium chloride, and 
again evaporated; a rose-pink color is produced. Succeeds only with 
nearly pure inosite. Gallois\ — Mercuric nitrate produces, in solutions of 
inosite, a yellow precipitate which, on cautious heating, turns red; the 
color disappears on cooling, and reappears on heating. 

Sorbin — obtained from the fermented juice of berries of the moun- 
tain ash, in which it is formed by the decomposition of malic acid. It 
forms colorless crystals, sweet, hard, and transparent ;. very soluble in 
water; very sparingly soluble in hot alcohol; its solutions are lsevogyrous, 
[«] D = — 35.97°; are not fermentable, but reduce Fehling's solution. 

Euealin — formed by the fermentation of melitose; it appears as a 
faintly sweet, syrupy liquid; dextrogyrous, [a] D =-f-50° about; it reduces 
cupro-potassic solutions, and is oxidized by nitric acid to oxalic acid. 



SACCHAROSES. 307 



Saccharoses, C 12 H 2S O n . 

Saccharose — Cane-sugar — Beet-sugar — is by far the most important 
member of the group; it has been known from early antiquity, and is 
very abundant in vegetable nature; it exists in many roots, fruits, and 
grasses, and is produced principally, not to say exclusively, from the sugar- 
cane, saccharum officinarum, sorghum, sorghum saccharatum, beet, beta 
vulgaris, and sugar-maple, acer saccharinum. 

For the extraction of sugar from the canes, these are crushed, the ex- 
pressed juice is drawn off into large pans, in which it is heated to about 
100°; milk of lime is now added, which causes the precipitation of impu- 
rities, albumen, wax, calcic phosphate, etc.; the clear liquid is drawn off, 
and "delimed" by passing a current of carbon dioxide through it; the 
clear liquid is again drawn off and evaporated, during agitation, to the 
crystallizing-point; the product is drained, leaving what is termed "raw" 
or " muscovado " sugar, while the liquid which drains off is molasses, 
Syruims fuscus (U. S.). The sugar so obtained is unfit for human con- 
sumption, and is purified by the process of "refining," which consists es- 
sentially in adding to the raw sugar, in solution, albumen in some form, 
filtering first through canvas, afterward through animal charcoal; the 
clear liquid is evaporated in " vacuum-pans " at a temperature not exceed- 
ing 72°, to the crystallizing-point; the product is allowed to crystallize in 
earthen moulds, a saturated solution of pure sugar is poured upon the 
crystalline mass in order to displace the uncrystallizable sugar which still 
remains, and the loaf is finally dried in an oven. The liquid displaced as 
above is what is known as " sugar-house syrup," a product which is now, 
however, largely and fraudulently produced from artificial glucose. 

Pure sugar should be entirely soluble in water; the solution should not 
turn brown when warmed with dilute potassium hydrate solution; should 
not reduce Fehling's solution; and should give no precipitate with ammo- 
nium oxalate. 

Beet-sugar is the same as cane-sugar, except that, as usually met 
with in commerce, it is lighter, bulk for bulk. "Sugar-candy," or "rock- 
candy," is cane-sugar allowed to crystallize slowly from a concentrated 
solution without agitation. Maple-sugar is a partially refined, but not 
decolorized variety of cane-sugar. 

Saccharose crystallizes, as usually seen, in small, white, monoclinic 
prisms; or as sugar-candy, in large, yellowish, transparent crystals; sp. 
gr. 1.606. It is very soluble in water, dissolving in about one-third its 
weight of cold water, and more abundantly in hot water; it is insoluble 
in absolute alcohol or ether, and its solubility in water is progressively 
diminished by the addition of alcohol. Aqueous solutions of cane-sugar 
are dextrogyrous, [«] D = + 73.8°. 

When saccharose is heated to 160° it fuses, and the liquid, on cooling, 
solidifies to a yellow, transparent, amorphous mass known as " barley- 
sugar"; at a slightly higher temperature it is decomposed into glucose 
and lsevulosan; at a still higher temperature, water is given off, and the 
glucose already formed is converted into glucosan; at 210° the evolution 
of water is more abundant, and there remains a brown material known as 
" caramel," or " burnt sugar," a tasteless substance, insoluble in strong 
alcohol, but soluble in water or aqueous alcohol, and used to communicate 
color to spirits; finally, at higher temperatures, methyl hydride and the 



308 GENEEAL MEDICAL CHEMISTRY. 

two oxides of carbon are given off; a brown oil, acetone, acetic acid, and 
aldehyde distil over, and a carbonaceous residue remains. 

If saccharose be boiled for some time with water, it is converted into 
inverted sugar, which is a mixture of glucose and laevulose: 

C.AA, + H a O = C e H„0 6 + C 6 H„0„ 

Saccharose. Water. Dextrose. Laevulose. 

With a solution of saccharose the polarization is dextrogyrous, but, after 
inversion, it becomes laevogyrous, because the left-handed action of the 
molecule of laevulose produced, [a] D =— 106°, is only partly neutralized 
by the right-handed action of the glucose, [a] D = + 57.6°. This inversion 
of cane-sugar is utilized in the testing of samples of sugar. On the other 
hand, it is to avoid its occurrence, and the consequent loss of sugar, that 
the vacuum-pan is used in refining — its object being to remove the water 
at a low temperature. 

Those acids which are not oxidizing agents act upon saccharose in 
three ways, according to circumstances: 1st, if tartaric and other organic 
acids be heated for some time with saccharose to 100° — 120°, compounds 
known as saccharides, and having the constitution of ethers, are formed; 
2d, heated with mineral acids, even dilate, and less rapidly with some or- 
ganic acids, saccharose is quickly converted into inverted sugar; 3d, con- 
centrated acids decompose cane-sugar entirely, more rapidly when heated 
than in the cold; with hydrochloric acid, formic acid and a brown, flocculent 
material (ulmic acid?) are formed; with sulphuric acid, sulphur dioxide 
and water are formed, and a voluminous mass of charcoal remains. Ox- 
alic acid, aided by heat, produces carbon dioxide, formic acid, and a brown 
substance (humine ?). 

Oxidizing agents act energetically upon cane-sugar, which is a good 
reducing agent. With potassium chlorate, sugar forms a mixture which 
detonates when subjected to shock, and which deflagrates when moistened 
with sulphuric acid. Dilute nitric acid, when heated with saccharose, 
oxidizes it to saccharic and oxalic acids. Concentrated nitric acid, alone 
or mixed with sulphuric acid, converts it into the explosive nitro-saccha- 
rose. Potassium permanganate, in acid solution, oxidizes it completely 
to carbon dioxide and water. 

Cane-sugar reduces the compounds of silver, mercury and gold, when 
heated with their solutions; it does not reduce the cupro-potassic solutions 
in the cold, but effects their reduction when heated with them to an ex- 
tent proportional to the amount of excess of alkali present. 

When ground up with potash, or moderately heated with liquor po- 
tassae, cane-sugar does not turn brown, as does glucose; but by long ebul- 
lition it is decomposed by the alkalies much less readily than glucose, 
with formation of acids of the fatty series and oxalic acid. 

With the bases, saccharose is capable of forming definite compounds 
called sucrates (improperly saccharates, a name belonging to the salts of 
saccharic acid). With calcium it forms no less than five compounds. 
Hydrate of calcium dissolves readily in solutions of sugar, with formation 
of a calcium compound, soluble in water, containing an excess of sugar; 
a solution containing one hundred parts of sugar in six hundred parts of 
water dissolves thirty-two parts of calcic oxide. These solutions have an 
alkaline taste; are decomposed, with formation of a gelatinous precipi- 
tate, when heated, and with deposition of calcium carbonate and regenera- 
tion of saccharose, when treated with carbon dioxide. Quantities of cal- 



SACCHAROSES. 309 

cium sucrates are frequently introduced into sugars to increase their 
weight — an adulteration the less readily detected, as the sucrate dissolves 
with the sugar. Calcium sucrates exist in the Liq. calcis saccharatus 
(B. P.). 

Yeast causes fermentation of solutions of cane-sugar, but only after 
its conversion into glucose; fermentation is also caused by exposing a 
solution of sugar containing ammonium phosphate to the air. 

During the process of digestion, probably in the small intestine, cane- 
sugar is converted into glucose. 

Lactose — Milk-sugar — Lactine — Saccharum lactis (U. S., Br.) — has 
hitherto been found only in the milk of the mammalia. It may be ob- 
tained from skim-milk by coagulating the casein with a small quantity of 
sulphuric acid, filtering, evaporating, redissolving, decolorizing with animal 
charcoal, and recrystallizing. 

It forms prismatic cn^stals; sp. gr. 1.53; hard, transparent, faintly 
sweet, soluble in six parts of cold water and in two and one-half parts of 
boiling water, soluble in acetic acid, insoluble in alcohol and in ether; its 
solutions are dextrogyrous, [#] D = + 59.3°. The crystals, dried at 100°, 
contains 1 aq., which they lose at 150°. 

Lactose is not altered by contact with air. Heated with dilute mineral 
or with strong organic acids, it is converted into galactose. Nitric acid 
oxidizes it to mucic and oxalic acids; a mixture of nitric and sulphuric 
acids converts it into an explosive nitro-compound. With organic acids 
it forms ethers. With soda, potash and lime it forms compounds similar 
to those of saccharose, from which lactose may be recovered by neutraliza- 
tion, unless they have been heated to 100°, at which temperature they are 
decomposed. If cupric sulphate solution be added to a solution of lactose 
and afterward potassium hydrate solution, a precipitate is formed which 
is redissolved in an excess of alkali; the cupric compound in this solu- 
tion is reduced, on boiling, with precipitation of cuprous oxide. Lactose 
also reduces Fehling's solution. 

In the presence of yeast, lactose is capable of alcoholic fermentation, 
which takes place slowly and, as it appears, without previous transforma- 
tion of the lactose into either glucose or galactose. On contact with 
putrefying albuminoids it enters into lactic fermentation. 

The average proportion of lactose in different milks is as follows: Cow, 
5.5 per cent.; mare, 5.5; ass, 5.8; human, 5.3; sheep, 4.2; goat, 4.0. 
When taken internally, it is converted into galactose by the pancreatic 
secretion; when injected into the blood, it does not appear in the urine, 
which, however, contains glucose. 

Maltose — A sugar closely resembling glucose in many of its proper- 
ties, and existing in malt, being the first product of the action of diastase 
upon starch. It crystallizes as does glucose, but differs from that sugar 
in being less soluble in alcohol and in exerting a dextrogyratory power 
three times as great. 

Melitose is obtained from the sweet exudation formed by various 
species of Australian eucalyptus (Australian manna), from which it may 
be extracted by solution in water, decolorization by animal charcoal, and 
crystallization. 

It crystallizes in long needles, with 3 aq., of which it loses two at 
100°, and the last at 130°; it is very soluble in water, the solutions being 
sweet, and dextrogyrous, [«] D = + 102°. 

Dilute acids convert it into glucose and eucalin; it is not colored when 
boiled with alkalies, nor does it reduce cupro-potassic solutions. 



310 GENERAL MEDICAL CHEMISTRY. 

Melezitose is obtained from an exudation of Larix europcea (Brian- 
con manna). It forms small, monoclinic prisms, sweet, efflorescent, very- 
soluble in water. Its solutions are dextrogyrous, [a] D =94.1°, do not re- 
duce cupro-potassic solutions, are not fermentable, and are converted, by 
boiling with dilute acids, into solutions of glucose. 

Trehalose is obtained from a Turkish manna, known as trehala. It 
crystallizes in hard octahedra with 2 aq., which it loses at 100°. It does 
not reduce Fehling's solution; is not fermentable, is very soluble in water; 
the solution being dextrogyrous, [a]„=+220°. 

Myeose is a sugar existing in ergot. It resembles trehalose in all its 
properties, except that it does not entirely lose its water of crystallization 
at 100°, and that it has a lower dextrogyratory action. 

Synanthrose exists, accompanied by inuline and glucose in the ripe 
tubercles of dahlia, helianthus, etc. It crystallizes with 1 aq. ; is not 
directly fermentable; has no action upon polarized light; is not colored 
by cold potash solution; and only reduces cupro-potassic solutions after 
prolonged boiling. 

Parasaecharose is an isomeric modification of cane-sugar, produced 
by the fermentation in summer of solutions of cane-sugar by exposure to 
air in the presence of ammonium phosphate. It differs from saccharose 
in its rotary power, [a] D =-L-107°; and- in its power to reduce alkaline 
solutions of cupric salts. 



Amyloses, n (C 6 H 10 O 5 ). 

Starch. — Amylum — the most important member of the group, is very 
widely disseminated in the vegetable kingdom, existing, as it does, in the 
roots, stems, and seeds of all plants. 

It is prepared extensively for use in the arts and as an article of diet 
from rice, wheat, potatoes, maniot, beans, sago, arrow-root, etc. The pro- 
cess generally followed consists in steeping the comminuted vegetable 
tissue for a considerable time in water rendered faintly alkaline with 
soda; the softened mass is then rubbed on a sieve under a current of 
water, which washes out the starch -granules; the washings are allowed 
to deposit the starch, which, after washing by decantation, is dried at a 
low temperature. 

Starch is a white powder, having a peculiar slippery feel, but it some- 
times appears in short columnar masses. The granules of starch have a 
similar appearance from whatever source they are obtained, yet those 
from different kinds of plants differ sufficiently to allow of their distinc- 
tion by microscopic examination. They are rounded or egg-shaped 
masses, having in the centre or toward one end a spot, called the hiliim, 
around which are a series of concentric lines, indicating the junctions of 
the various layers of which the granules are composed — these markings 
varying in character and distinctness in different plants. The main char- 
acters of the principal kinds of starch are given in the table on next page. 

Starch is not altered by exposure to air, from which, however, it ab- 
sorbs moisture; commercial dried starch contains eighteen per cent, of 
moisture, of which it loses eight per cent, in vacuo, and the remaining 
ten per cent, when heated to 145°. It is insoluble in alcohol, ether, cold 
acids, and cold water. If fifteen to twenty parts of water be gradually 
heated with one part of starch, the granules swell at about 55°, and at 
80° they have reached thirty times their original dimensions; their struc- 



AMYLOSES. 



311 



ture is no longer distinguishable, and they form, by their agglutination 
with each other, a translucent, gelatinous mass, commonly known as 
starch paste; in this state the starch is said to be hydrated, and, if boiled 
with much water and the liquid filtered, a solution of starch passes 
through, which is opalescent from the suspension in it of undissolved 
particles. Dilute solutions of the alkalies produce the same effects on 
starch in the cold as does hot water. Hydrated starch is dextrogyrous, 
[a] D ^+216°. 

Characters of Starch-Granules. 



From 


Average size in 
millimetres. 


Shape. 


Hilum. 


Rings. 


Tous les mois 


.0939— .0469 
.0304— .0609 
.01 —.07 
.0375— .0327 
.0376— .'0686 
.0376— .... 
.0342— .... 
.0469— .... 
.028 — . . . . 
.0376— .... 
.0343— .... 
.0177— .0282 
.0282— .... 
.005 —.0005 
.014 — .... 
.0188— .... 
.0188— .... 
.0022— .216 
.0185— .07 
.0375— .0022 
.0022— .022 
.0188— .... 
.0282— .066 
.0188— .014 
.014 — .... 
.0094— .... 
.019 —.0094 
.0076— .005 


Oval 

Irreg. oval. . 

Ovoid 

Ovoid 

Circ. ovate. 
Ovoid 

Pear 

Elongated . 

Oval 

Oval 

Oval 

Oval 

Polygonal. . 
Pentagonal, 
Hexagonal . 


Ex 

Ex. ft... 
Central. . 
Ex 

Central. . 

CI 

CI 

CI 

Ft 

CI 

Stellate . 

Stellate . 

Linear . . 

Central.. 


In. F. R. 


Curcuma arrow-root 

Maranta arrow-root 

Natal arrow-root 

Potato 


In. CI. 

CI." 
CI. 


Ginger 




Galangal 


Ft. 


Calumba 


Ft. C. 


Orris-root 




Turmeric 


In. CI. 


Bean 


Ft. 


Pea 


Ft. 




Ft. 


Pepper 






Ft. 


Dari 




Ft. 


Maize "... 


Round .... 




Ft. 


Wheat 


Round .... 
Round .... 
Round .... 

Elliptic 

Round 
Oval 

Conical. . . . 
Truncated. . 
Polyhedral . 


Inv 

Inv 

Ex 

Ex 

Ex 

Ex 


Inv. 


Barley 


Inv. 


Rye 


Inv. 


Chestnut 


Inv. 


Acorn 


Inv. 


Sago 


Ft. 






Arum arrow-root 

Oat 


Ft. 


Tahiti arrow-root 

Rice 


Truncated. . 
Polygonal. . 1 


Stellate . 
Stellate . 










Ex.=:excentric; In. — incomplete; F. =fine; R.=regular; Ft. = faint; 
CI. = clearly defined; C. = complete; Inv.=invisible. 

When subjected to dry heat, the granules of starch swell and burst; 
at 200° it is converted into dextrin; at 230° it forms a brownish yellow 
fused mass, composed principally of pyrodextrin. Hydrated starch is 
converted into dextrin by heating with water at 160 a , and, if the action 
be prolonged, the new product is changed to glucose. 



812 



GENERAL MEDICAL CHEMISTRY. 



If starch be ground up with dilute sulphuric acid, after about half an 
hour the mixture gives only a violet color with iodine (see below); if now 
the acid be neutralized with chalk and the filtered liquid evaporated, it 
yields a white, granular product, which differs from starch in being sol- 
uble in water, especially at 50°, and in having a lower rotary power, 
[#] D =+211°. If the action be prolonged, the value of [&] D continues to 
sink until it reaches +73,7°, when the product consists of a mixture of 
dextrin and glucose. Concentrated nitric acid dissolves starch in the 
cold, forming a nitro-product called xylodin or pyroxam, which is insol- 
uble in water, soluble in a mixture of alcohol and ether; explosive. Hy- 
drochloric and oxalic acids convert starch into glucose. When starch is 
heated under pressure to 120° with stearic or acetic acid, compounds are 
formed w T hich seem to be ethers, and to indicate that starch is the hydrate 
of a trivalent, oxygenated radical, (C 6 H 7 2 ) ; ". Tannic acid produces in 
cold solutions of starch a precipitate, soluble at 50°, and deposited on 
cooling. Potash and soda in dilute solutions convert starch into the sol- 
uble modification mentioned above. 

A dilute solution of iodine produces a more or less intense blue-violet 
color with starch, either dry, hydrated, or in solution, the color disappearing 
on the application of heat, and returning on cooling; if to a solution of 
starch, blued by iodine, a solution of a neutral salt be added, there sep- 
arates a blue, flocculent deposit of the so-called iodide of starch. Iodine 
renders starch soluble in water, and a soluble iodized starch is obtained 
by triturating together nine parts of starch, two parts w T ater, and one part 
iodine; the mixture is then heated over the water-bath for two hours, 
cooled, and precipitated by the addition of the proper quantity of alcohol. 

The amount of starch contained in food vegetables varies from about 
five per cent, in turnips to 8\) per cent, in rice, as will be observed in the 
following table: 



Composition of Vegetable Foods. 





Nitrogen- 
ized matter. 


Starch. 


Dextrin, 
etc. 


Cellu- 
lose. 


Fat. 


Mineral 
matter. 


Carbo- 
hydrate. 


1 
Water 


Vegetable 
fibre, etc. 


Authority. 


Wheat, hard 

Wheat, semi-hard.. 
Wheat, soft 

Barley 


22.75 

19.50 

20.0 

15.25 

12.65 

12.50 

12.96 

14.39 

12 50 

7.55 

14.45 

10.80 

8.10 

12.60 

13.10 

22.86 

19.0 

30.80 

29.(5 

25.50 

23.80 

25.20 

2.50 

2.10 

1.50 

1.30 

1.10 

1.20 


58.62 
65.07 
63.80 
70.05 
76.51 
64.65 
66.43 
60.59 
67.55 
88.65 

64.*90 

56.80 

60.0 

48.30 

55.85 

55.70 

58.70 

56.0 

20.0 

18.80 

16.05 

8.40 

9.60 

5.10 


9.50 
7.60 
8.0 
7.0 
605 
14.90 
10.0 
9.25 
4.0 
1.0 

1.09 
3.20 
10.20 
6.10 
5.80 
2.10 


3.50 

3.0 

3.10 

3.0 

2.80 

3.10 

4.75 

7.06 

5.90 

1.10 

3.50 

3.0 

1.05 

2.09 

3.50 

2.40 

1.04 

0.45 


2.61 
2.12 
2.25 
1.95 

1.87 

2.25 

2.76 

5.50 

8.80 

0.80 

1.25 

2.0 

1.60 

5.60 

3.0 

5.74 

5.0 

1.90 

2.0 

2.80 

2.10 

2.60 

0.11 

0.20 

0.30 ! 

0.20 

0.50 


3.02 

2.71 

2.85 

2.75 

2.12 

2.60 

3.10 

3.25 

1.25 

0.90 

1.60 

1.70 

2.30 

3.0 

2.50 

5.05 

3.50 

3.(55 

3.20 

2.10 

2.30 

1.26 

0.70 

2.6G 

1.0 

1.0 

0.60 


68.48 
70.50 
51.00 
63.80 


14.22 

15.0 

37.0 

15.0 

13.0 

16.0 

12.50 
8.40 
9.90 
8.30 

11.50 

74.0 

75 

67.50 

83.0 

82.0 

91.0 


9^53 

l'.io 


Pay en. 
Payen. 
Pay en. 
Payen. 
Payen. 
Payen. 
Payen. 


Oats 


Payen. 


Maize 


Payen. 


Rice 


Payen. 




Payen. 


Flour 


Letheby. 


Bread 


Letheby. 


Oatmeal 


Letheby. 


Buckwheat 

Quinoa seeds 

Quinoa flour 

Horse-bean 

Broad bean 

White bean 

Peas, dried 

Lentils 


Payen. 

Voelcker. 

Voelcker. 

Payen. 

Payen. 

Payen. 

Payen. 

Payen. 


Potato 


Paven. 


Potato 

Carrots 


Letheby. 

Payen. 

Letheby. 




Letheby. 




Letheby. 







AMYLOSES. 313 

Starch has not been found in the animal economy outside of the ali- 
mentary canal, in which, as a prerequisite to its absorption, it must be 
converted into dextrin and glucose. This change is partially effected by 
the action of the saliva, more rapidly with hydrated than with dry starch, 
and more rapidly with the saliva of some animals than that of others, those 
of man and of the rabbit acting much more quickly than those of the horse 
and dog. The greater part of the starch taken with the food passes into 
the small intestine unchanged; here, under the influence of the pancreatic 
ferment, the most complete transformation into glucose, and of a portion 
into lactic and butyric acids, takes place. If, however, the diet is abnor- 
mally rich in starch, a portion is wasted, passing out unchanged in the 
faeces. 

Glycogen. — This interesting body, which has been the subject of 
much discussion, was discovered by CI. Bernard in the liver, and subse- 
sequently in the placenta; it has also been found to exist in white blood- 
corpuscles, pus-cells, young cartilage-cells, in many embrionic tissues, and 
in muscular tissue. During the activity of muscles the amount of glyco- 
gen which they contain is diminished, and that of sugar increased. 

It is best obtained from the liver; the organ is removed as quickly as 
possible after death, ground or cut into small pieces, which are immedi- 
ately thrown into boiling water; it should not be subjected to prolonged 
boiling, but, the water being poured off, the pulp is expressed and the 
united liquids filtered and evaporated over the water-bath to a small 
bulk; the cooled solution is precipitated with glacial acetic acid, or, bet- 
ter, with alcohol; the precipitate is collected, redissolved in water; the 
solution filtered through animal charcoal, and again, after concentration 
if necessary, precipitated by alcohol. 

Pure glycogen is a snow-white, floury powder; amorphous, tasteless, 
and odorless; soluble in water, insoluble in alcohol and ether; in water it 
swells up at first, and forms an opalescent solution, which becomes clear 
on the addition of potash. According to Hoppe-Seyler, its solutions are 
dextrogyrous to about three times the extent of those of glucose. 

Dilute acids, ptyalin, pancreatin, extract of liver-tissue, blood, dias- 
tase, and albuminoids convert glycogen into a sugar having all the prop- 
erties of glucose. Cold nitric acid converts it into xyloidin; on boiling, 
into oxalic acid. Its solutions dissolve cupric hydrate, which is, how- 
ever, not reduced on boiling. Iodine colors glycogen wine-red. 

Concerning the method of formation of glycogen in the economy, but 
little is known with certainty; there is little room for doubting, however, 
that while the bulk of the glycogen found in the liver results from mod- 
ification of the carbohydrates, it may be and is produced from the al- 
buminoids as well. The ultimate fate of glycogen is undoubtedly its 
transformation into sugar under the influence of the many substances 
existing in the body capable of provoking that change. 

Dextrin, British gum, a substance resembling gum arabic in appear- 
ance and in many properties, is obtained by one of three methods: 1st, 
by subjecting starch to a dry heat of 175°, known as the baking process; 
2d, by heating starch with dilute sulphuric acid to 90° until a drop of 
the liquid gives only a wine-red color, neutralizing with chalk, filtering, 
concentrating, precipitating with alcohol; the product so obtained almost 
always contains glucose; 3d, by the action of diastase (infusion of malt) 
upon hydrated starch; as soon as the starch is dissolved the liquid must 
be rapidly heated to boiling to prevent saccharification. The product is 
also usually contaminated with glucose. 



314: GENERAL MEDICAL CHEMISTRY. 

Dextrin is a colorless, or yellowish, amorphous powder, soluble in water 
in all proportions, forming syrupy liquids; when obtained by evaporation 
of its solution, it forms masses resembling gum arabic in appearance. 
Dextrogyrous, [a] D = + 138.88°. 

Nitric acid oxidizes dextrin, not to mucic acid, as it does the srums, 
but to oxalic acid; a mixture of nitric and sulphuric acids converts it 
into a dinitro-compound. Dextrin reduces the cupro-potassic solutions 
at 85°. By iodine it is colored light wine-red. 

Dextrin has been found to exist in the blood, lungs and other organs 
of carnivora and herbivora, and in the contents of the intestine. 

Inulin — Helenin — Dahlinin — Menyanthin — a substance resembling 
starch, obtained from the roots of certain vegetables; it differs from starch 
in being converted by prolonged contact with boiling water into a lasvogy- 
rous, uncrystallizable sugar; in being itself lsevogyrous, [«]„=— 34. 4° 
(?), in not being colored blue by iodine, and in reducing, when heated, in 
the presence of ammonia, the salts of copper and silver. 

Tunicin, a cellulose-like substance which constitutes the organic 
portion of the mantle of certain molluscs. It withstands the action of 
reagents better than cellulose, but may be converted into a sugar by sul- 
phuric acid. 

Cellulose — Cettulin — Lignin — forms the basis of all vegetable tis- 
sues; it exists, almost pure, in the pith of elder and of other plants, in the 
purer, unsized papers, in cotton, and in the silky appendages of certain 
seeds. Cotton, freed from extraneous matter by boiling with potash, and 
afterward with dilute hydrochloric acid, yields pure cellulose. 

It is a white material, having the shape of the vegetable structure 
from which it was obtained; insoluble in the usual neutral solvents, but 
soluble in the deep blue liquid obtained by dissolving copper in ammonia 
in contact with air. 

By the action of reagents upon cellulose, as paper and cotton, several 
valuable products are obtained. 

Vegetable parchment, or parchment paper, a tough material, possess- 
ing all the valuable properties of parchment, is made by immersing un- 
sized paper for an instant in moderately strong sulphuric acid, washing 
thoroughly, and drying. 

Nitro -cellulose. By the action of nitric acid upon cellulose, cotton, 
three different products of substitution may be obtained: mononitro-cel- 
lulose, soluble in acetic acid, insoluble in a mixture of ether and alcohol; 
dinitro-cellulose, insoluble in acetic acid, soluble in a mixture of ether 
and alcohol; trinitro- cellulose, soluble in both the above solvents. Pro- 
ducts known as gun-cotton ox pyroxylin, composed of varying proportions 
of these three derivatives, are obtained for use in the arts. When gun-cot- 
ton is required as an explosive agent, the process is so managed that the 
product shall contain the greatest possible proportion of trinitro-cellu- 
lose, the most readily inflammable of the three. When required for the 
preparation of collodion for use in medicine or in photography, dinitro- 
cellulose is the most valuable. To obtain this, a mixture is made of equal 
weights of nitric and sulphuric acids (of each about five times the weight 
of the cotton to be treated); in this the cotton is immersed and well 
stirred for about three minutes, after which it is well stirred in a large 
vessel of water, washed with fresh portions of water until the washings 
are no longer precipitated by barium chloride, and dried. Collodion is 
a solution of dinitro-cellulose in a mixture of three volumes of ether and 
one volume of alcohol. 



BENZENE. 



315 



Gums are substances of unknown constitution, existing in plants; 
amorphous; soluble in water, insoluble in alcohol; converted into glucose 
by boiling with dilute sulphuric acid. 

Lichenin is obtained from various lichens by extraction with boiling 
water, forming a jelly on cooling; it is oxidized to oxalic acid by nitric 
acid; is colored yellow by iodine; and is precipitated from its solutions 
by alcohol. 

Arabin is the soluble portion of gum arabic and gum Senegal — Aca- 
cia (U. S. P.) — in which it exists in combination with potassium and 
sodium. To separate arabin, gum arabic is dissolved in water acidulated 
with hydrochloric acid, and precipitated by alcohol. It is a white, amor- 
phous, tasteless substance, which is not colored by iodine; is oxidized by 
nitric acid to mucic and saccharic acids; is converted by sulphuric acid 
into a non-fermentable sugar, arabinose / and has the composition, 

C„H,.O l . + l Aq. . 

Bassorin constitutes the greater part of gum tragacanth; it is in- 
soluble in water, but swells up to a jelly in that fluid. 

Cerasin is an insoluble gum exuded by cherry- and plum-trees; water 
acts upon it as upon bassorin. 



FIFTH SERIES OF HYDROCARBONS. 

Series C n H 2n _ 6 . 

The hydrocarbons of this series are the starting-points from which 
the major part of that numerous and important class of substances usually 
classed as aromatic are obtainable or derivable. Those of the series at 
present known are: 



Benzene. . . C 6 H 6 
Toluene . . . C 7 H 8 
Xylene .... C 8 H 1( 



boils at 80.4° 
boils at 110.3° 
boils at 142.0° 



Cumene 
Cymene 
Laurene 



C 9 H ia 

C io H n 

C, H 



boils at 151.4° 
boils at 175.0° 
boils at 188.0° 



Benzene. 

Benzol — phenyl hydride — C 6 H 6 (not to be confounded with the com- 
mercial benzine, a mixture of hydrocarbons of the series C n H 2n + 2 , ob- 
tained from petroleum). — This important substance, which may be con- 
sidered as the basis of all the aromatic compounds, was discovered by 
Faraday in 1825, among the products of the distillation of the fatty oils. 

It does not exist in nature, but is produced in a great number of re- 
actions. It is obtained by one of two methods, according as it is required 
chemically pure or mixed with other substances. 

To obtain it pure, recourse must be had to the decomposition of one 
of its derivatives, benzoic acid; this substance is intimately mixed with 
three parts of slacked lime, and the mixture heated to dull redness in an 
earthenware retort connected with a well-cooled receiver; the upper layer 
of distilled liquid is separated, shaken with potassium hydrate solution, 
again separated, dried by contact with fused calcium chloride, and redis- 
tilled over the water-bath. 

For use in the arts, and for most chemical purposes, benzene is ob- 
tained from coal- or gas-tar, an exceedingly complex mixture, containing 
some forty or fifty substances, among which are: 



316 



GENERAL MEDICAL CHEMISTRY. 



Hydrocarbons. 


Acids. 




Bases. 


Benzene. 


Acenaphthalene. 


Carbolic. 


Pyridine. 


Iridoline. 


Toluene. 


Fluorene. 


Cresylic. 


Aniline. 


Cryptidine 


Xylene. 


Anthracene. 


Phlorylic. 


Picoline. 


Acridine. 


Cumene. 


Retene. 


Rosolic. 


Lutidine. 


Coridine. 


Cymene. 


Chrysene. 


Oxyphenic. 


Collidine. 


Rubidine. 


Naphthalene. 


Pyrene. 




Leucoline. 


Viridine. 



By a primary distillation of coal-tar the most volatile constituents, in- 
cluding benzene, are separated as light oil; this is washed, first with sul- 
phuric acid, and then with caustic soda, and afterward redistilled; that 
portion being collected which passes between 80° and 85°. This is the 
commercial benzene, a product still contaminated with the higher homo- 
logues of the same series, from which it is almost impossible to separate 
it, but whose presence is rather advantageous than otherwise to the prin- 
cipal use to which benzol is put — the manufacture of aniline dyes. 

Benzene is a colorless, mobile liquid, having, when pure, an agreeable 
odor; sp. gr. 0.86 at 15°; crystallizing at -J- 4.5°; boiling at 80.5°; very 
sparingly soluble in water, soluble in alcohol, ether, and acetone. It dis- 
solves iodine, sulphur, phosphorus, resins, caoutchouc, gutta-percha, and 
almost all the alkaloids. It is inflammable, and burns with a luminous, 
smoky flame. 

Benzene unites with chlorine or bromine to form products of addi- 
tion, or of substitution; the corresponding iodine compounds can only be 
obtained by indirect methods. Sulphuric acid combines with benzene to 
form a neutral substance, sulpho-benzide, when the anhydrous acid is 
used, and phenyl- sulphurous acid with the ordinary sulphuric acid. 

The action of nitric acid upon benzene is of great commercial inter- 
est; if fuming nitric acid of sp. gr. 1.52 be slowly added to benzene, a 
reddish liquid is formed; from which, on the addition of water, a reddish 
yellow oil separates, and is purified by washing with water and with so- 
dium carbonate solution, drying and rectifying; this oily material is mono- 
nitro-benzene (see pp. 319, 333). If benzol be boiled with fuming nitric 
acid, or if it be dropped into a mixture of nitric and sulphuric acids, so 
long as the fluids mix, a crystalline product, dinitro-benzene, is formed. 

The constitution of benzene, the nucleus of the aromatic compounds, 
differs much in character from that of the hydrocarbons of the series hith- 
erto considered, and is of importance in connection with the formation of 
its numerous derivatives. Writing the molecular formulae of the sixth of 
each of the first three series (the constitution of those of the terebenthene 
series is still doubtful) we have: 



First Series. 

C=H 3 


Second Series. 

1 


Third Series 

C = H 3 


1 
C = H 2 


1 

C = H 2 

1 


C = H 2 

1 


1 
0=H 2 


C = H 2 


C = H 2 


C = H 2 


C = H 2 

1 


C = H 2 


1 
C = H 2 

1 
CeeH 3 


C-H 

C = H 2 


J 

' ill 
C-H 


C 6 H 14 


C 6 H ia 


C 6 S 10 



BENZENE. 31 T 

and those of the second term (the first being necessarily absent in the 
second and third series): 

C = H S C = H, C-H 

I II II! 

C = H 3 C = H, C-H 

2 H 6 C 2 H 4 C,H, 

It will be observed that in each of these the chain of carbon atoms is 
an open one, and that the series differ in this, that in the first, each of the 
atoms of carbon exchanges with its neighbor a single valence; in the 
second, two neighboring carbon-atoms exchange two valences between 
them; and that in the third there is an exchange of three valences be- 
tween two neighboring carbon-atoms. And, further, that in terms above 
the second in the first two series, and the third in the third series, supe- 
rior homologues may be considered as formed by interpolation of CH a in 
the chain of the one next below. 

In the case of benzene, Kekule has advanced the theory, according to 
which alone the formation of the benzene derivatives can be explained, 
and against whose adoption no reason based upon experiment has been ad- 
vanced; that the carbon atoms of the benzene molecule are arranged, not 
in an open, but a closed chain, that they exchange with each other alter- 
nately one and two valences, and that consequently the molecular for- 
mula of benzol is: 

H 

I 
C 

H x ^\ /H 

X C C x 

I II 

h/° x/ c \h 
c 

I 

H 

Further, that the superior homologues of benzene are derived from it 
by the substitution of CH 3 for H, and that all the derivatives of benzol 
are formed by such substitution of a group or groups for an atom or atoms 
of hydrogen, in such a way that they all contain one or more groups of 
six atoms of carbon arranged as above: 

H H 



I 





H-C C-CeeH 3 H-C C-O-H 

J - II I II 

H-C C-H H-C C-H 

Y V 

i i 

H H 

Toluene. Phenol (carbolic add). 



318 GENERAL MEDICAL CHEMISTRY. 

H H 

I I 

c c 

H-C C-(N0 2 )' H-C C-(NH 2 )' 

I I! I II 

H-0 C-H H-C C-H 

\/ \/ 

c c 

I I 

H , H 

Nitrobenzene. Amido-benzene (aniline). 

Toluene. 

Toluol — Methyl-benzene — C 6 H 6 ,CH 3 — exists in the products of distilla- 
tion of wood, coal, etc., and as one of the constituents of commercial ben- 
zene; in Rangoon tar, a native mineral oil. It has been formed synthetic- 
ally by acting upon a mixture of monobromo-benzene and methyl iodide 
"with sodium. It is obtained, with considerable difficulty, by fractional 
distillation from coal-tar. 

It is a colorless liquid, having a peculiar odor, differing somewhat from 
that of benzene; boils at 110.3°; does not solidify at — 20°; sp. gr. 0.872 
at 15°; almost insoluble in water, soluble in alcohol, ether, carbon disul- 
phide. It burns with a bright, but very smoky flame. 

It yields a number of derivatives similar to those of benzene, among 
which may be mentioned nitro-toluene and toluidine, the homologues of 
nitro-benzene and aniline, which accompany those substances in the com- 
mercial products; cresylol, the superior homologue of carbolic acid, and 
benzylic alcohol. 

Xylene — Xylol — Dimethyl-benzene — C 6 H 4 (CH 3 ) 2 — accompanies its in- 
ferior homologues in coal-tar. When pure it is a liquid of an aromatic 
odor; sp. gr. 0.865 at 20°; boils at 142°; insoluble in water, soluble in 
ether, benzene, etc., sparingly soluble in alcohol. 

There are three isomeric substances having this composition, and 
differing in the position in which the substituted CH 3 groups are placed. 
Each of these corresponds to a series of derivatives parallel to those of 
benzene. 

Cumene — Cumol — Propyl-benzene — C 6 H 5 (C 3 H 7 ) — is obtained by dis- 
tilling a mixture of cuminic acid and lime, as benzene is prepared from 
benzoic acid. It is a limpid liquid, having a strong aromatic odor; boils 
at 151.4°; insoluble in water, very soluble in alcohol and ether. 

There are several isomeres of this substance, among which are pseudo- 
cumene, or trimethyl-benzene, C 6 H 3 (CH 8 ) 3 , and mesitylene, or methyl-ethyl- 
benzene, C 6 H 4 (CH 3 )(0 2 H E .); each corresponding to a series of derivatives. 

Cymene — Cymol — there are many isomeres, of which one exists ready 
formed in essence of cumin, and in hemlock. It is a colorless, oily liquid; 
has an odor of lemon; sp. gr. 0.857 at 16°; boils at 175°; insoluble in water, 
but readily soluble in alcohol, ether, and essential oils. 

Laurene — is an imperfectly studied body, obtained by the decompo- 
sition of camphor by zinc chloride. It is a colorless liquid, boiling at 188°; 
sp. gr. 0.887 at 10 c 



\0 



PHENOLS. 319 



Nitro-derivatives. 

The products of this class are quite numerous, among them the only 
one calling for consideration here is: 

Nitrobenzene — nitro-benzol — mono-nitro-benzene — essence of Mir- 
bane — C 6 H 6 (N0 2 ) — this important substance, whose production lies at the 
root of the aniline industry, was discovered by Mitscherlich, and is formed 
by the action of nitric acid upon benzene. 

Benzol is slowly added to fuming- nitric acid, or to a mixture of nitric 
and sulphuric acids, care being taken to agitate the mixture and to pre- 
vent elevation of temperature ; the nitro-benzene formed is decanted, 
repeatedly washed with solution of sodium carbonate and with water. 
The result of this process is sufficiently pure for industrial uses; if re- 
quired in a state of greater purity, it may be distilled — a process, however, 
attended with considerable loss. 

Nitro-benzene is a yellowish liquid; has a sweet taste and a pronounced 
odor of bitter almonds; sp. gr. 1.209 at 15°; boils at 213°; almost insolu- 
ble in water, very soluble in alcohol and ether. 

Chlorine and bromine do not attack it at ordinary temperatures. 
Concentrated sulphuric acid dissolves it, and, at the boiling temperature, 
decomposes it; boiled with fuming nitric acid, it is converted into binitro- 
benzene; with ordinary nitric or sulphuric acid, it may be distilled un- 
changed. It is attacked by potash with difficulty. 

The most important reaction of nitro-benzene is that with reducing 
agents; a great number of which convert it into aniline (q. v.). 

Under the names essence of mirbane and artificial essence of bitter 
almonds, this substance has been used in perfumery to a considerable ex- 
tent — a use which cannot be too strongly condemned, as nitro-benzol is, as 
well in the form of vapor as in that of liquid, an active poison. When 
taken internally, even in a dose of a few drops, it has caused death in 
several instances, although recovery has followed the taking of a con- 
siderably larger dose. Inhalation of its vapor, even when largely diluted 
with air, produces headache, drowsiness, difficulty of respiration, cardiac 
irregularity, more or less loss of muscular power, convulsions, coma. 
Obviously, the frequent inhalation, even in small quantities, of a substance 
such as this, is to be avoided. 

Nitro-benzol can be distinguished from benzoic aldehyde by sulphuric 
acid, which does not color the former; and by the action of acetic acid 
and iron filings, which convert nitro-benzene into aniline, whose presence 
is indicated by the reactions on p. 333. 



Phenols. 

The hydrocarbons of this series, unlike those previously considered, 
form by substitution two distinct series of hydrates, which differ from each 
other materially in their properties. The terms of one of these series 
possess all the functions of the alcohols, and are therefor known as the 
aromatic alcohols (see p. 323). The terms of the other series differ in 
function from any substance thus far considered, and are known as 
phenols, the difference between them and the aromatic alcohols being 



320 GENERAL MEDICAL CHEMISTRY. 

probably due to the fact that in the phenols the OH is directly attached 
to a carbon atom, while in the alcohols it is substituted for an atom of 
hydrogen of a substituted hydrocarbon group, thus: 

H H 

I I 

C C 

H-C C-CH 3 H-C C-CH 2 OH 

I II I II 

H-C C-OH H-C C-H 

\/ \/ 

c c 

H H 

Benzylic phenol. Benzylic alcohol. 

The phenols differ from the alcohols in many particulars: in not fur- 
nishing by oxidation corresponding aldehyds and acids; in not dividing 
into water and hydrocarbon under the influence of dehydrating agents; 
in not reacting with acids to form ethers; in combining to form directly 
products of substitution with chlorine, bromine and nitrosyl; and in form- 
ing with metallic elements compounds more stable than similar compounds 
of the true alcohols. In short, the phenols appear to have, besides an 
alcoholic function, more or less of the function of acids. 



Phenol. 

Phenyl hydrate — JPhenic acid — Carbolic acid — Acidum carbolicum 
(U. S., Br.) C 6 H B OH — exists in considerable quantity in coal- and wood- 
tar, and in small quantity in castoreum, and possibly in urine. 

It is formed in a number of reactions: 1st, by fusing sodium phenylsul- 
phite with an excess of alkali; 2d, by heating phenyl iodide with potas- 
sium hydrate to 320°; 3d, by heating together salicylic acid and quick- 
lime; 4th, by total synthesis from acetylene; 5th, by dry distillation of 
benzoin. 

The source from which it is exclusively obtained is coal-tar, or rather 
that portion of the product of distillation of coal-tar which passes over be- 
tween 150° and 200°. This is treated with a saturated solution of potash 
containing undissolved alkali; a solid phenate is formed, which is dissolved 
in hot water; the liquid is allowed to separate into two layers, the lower 
of which is drawn off and neutralized with hydrochloric acid; the phenol 
rises to the surface, is separated, washed with water, dried over calcium 
chloride, redistilled, crystallized at —10°, and the crystals drained. 

Pure phenol crystallizes in long, colorless, prismatic needles, fusible at 
35°, boiling at 187°. It has a peculiar, well-known odor, and an acrid, 
burning taste; very sparingly soluble in water, readily soluble in alcohol 
and in ether; sp. gr. 1.065 at 18°; neutral in reaction. On contact with 
the skin or with mucous surfaces, it produces a white stain; it coagulates 
albuminoids, and is a powerful antiseptic. 



PHENOL. 321 

Phenol is capable of distillation without decomposition, and at a red 
heat is only partially decomposed, with formation of a small quantity of 
naphthalin. On contact with damp air it absorbs moisture to form a 
hydrate, which crystallizes in six-sided prisms, fusible at 16°, which loses 
its water at 187°. Vapor of phenol is reduced to benzene when heated 
with zinc-filings. 

It combines with sulphuric acid to form sulpho-conjugate acids 
(phenylsulphuric acids). With concentrated hydriodic acid at 280° it yields 
benzene. Nitric acid converts it into nitro-derivatives, differing with the 
concentration of the acid used; with an acid of 36° B. it forms trinitro- 
phenic or picric acid (q. v.). When heated with sulphuric and oxalic 
acids, it forms a colored substance known as corallin or rosolic acid; this 
is a mixture from which several beautiful pigments, aurin, peonin, 
azulin, and phenicin, are obtained. 

Phenol may be recognized by the following reactions: 1st, its peculiar 
odor; 2d, the formation of the yellow picric acid with nitric acid of 36° B. ; 
3d, the production of a blue or green color when treated with a small 
quantity of ammonium hydrate and a trace of solution of a hypochlorite; 
4th, a lilac color produced on the addition of a small quantity of ferric 
sulphate; 5th, a yellowish white precipitate with bromine water; 6th, pre- 
cipitation of albuminoids. Of these reactions, 3d, 4th, and 5th are very 
delicate. 

Toxicology. — The use of carbolic acid in medicine, both for external 
use as one of the most valuable of antiseptics, and for internal adminis- 
tration, has of late years become widely extended. The energy of its 
caustic action upon living tissues, and of its power of coagulation of the 
albuminoids, render it very actively injurious when taken internally, and 
although its odor prevents, in a great measure, its ingestion by mistake, 
or its administration with murderous intent; yet such cases have occurred, 
and instances in which it is taken suicidally are becoming exceedingly 
common. Woodman and Tidy cite twenty-one cases of poisoning by 
phenol occurring during the years of 1868 to 1873, among which there 
was but one recovery, the doses taken being usually one to two ounces, 
a quantity certainly much greater than the minimum lethal dose; in one 
instance death followed the application of carbolic acid to a wound. 

When this poison has been taken, the mouth is whitened by its caustic 
action; there is a marked odor of carbolic acid in the breath. The acid 
is eliminated by the urine, partly unchanged, and partly in the form of 
colored derivatives, which communicate to the urine a greenish, brownish, 
or even black colour; biliary acids are also usually present. 

The treatment consists in the administration of albumen (white of egg) 
and of emetics. 

To detect phenol in the urine, that liquor must not be distilled with 
sulphuric acid, as sometimes recommended, as it contains normally sub- 
stances which by such treatment yield carbolic acid. The best method is 
that of Landolt, which consists in adding an excess of bromine water to 
about 500 c.c. of the urine; on standing some hours, a yellowish precipi- 
tate collects at the bottom of the vessel; this is removed, washed, and 
treated with sodium amalgam, when the characteristic odor of phenol is 
developed. From other parts of the body, phenol may be recovered by 
acidulating with tartaric acid; distilling; extracting the distillate by 
shaking with ether; evaporating the ethereal solution; extracting the 
residue with a small quantity of water, and applying to this solution the 
tests described above. 
21 



322 GENERAL MEDICAL CHEMISTRY. 

Trinitrophenol — Picric acid — Trinitrophenic acid — C 6 H 2 (N0 2 ) a 
OH. — This substance, the method of whose formation has been given 
above, is derived from phenol by the substitution of three groups (NO ) 
for three atoms of hydrogen; it is the only one of the numerous substi- 
tution products of phenol which is of sufficient medical interest for con- 
sideration here. 

It crystallizes in brilliant, yellow, rectangular plates, or in six-sided 
prisms; it is odorless, and has an intensely bitter taste, whence its more 
common name (from 7n.Kp6s= bitter); it is acid in reaction; sparingly 
soluble in water, very soluble in alcohol, ether, and benzene; it fuses at 
122.5°, and may, if heated with caution, be sublimed unchanged; but, if 
heated suddenly or in quantity, it explodes with violence. 

Trinitrophenol behaves as a monobasic acid, forming salts, which are 
for the most part soluble, yellow, crystalline, and decompose with explo- 
sion when heated. 

The presence of picric acid is detected by: 1st, its intensely bitter 
taste; 2d, its alcoholic solution when shaken with a potassium salt gives 
a yellow crystalline precipitate; 3d, an ammoniacal solution of cupric 
sulphate gives a green, crystalline precipitate; 4th, glucose heated with a 
dilute alkaline solution of picric acid, communicates to it a blood-red 
color; 5th, warmed with an alkaline solution of potassium cyanide, an in- 
tense red color is produced (the same effect is produced by ammonium 
sulphydrate); 6th, unbleached wool, immersed in boiling solution of picric 
acid, is dyed yellow. Nos. 1, 3, 5 and 6 are quite delicate. 

Picric acid stains animal tissues yellow, and is used for that purpose 
by histologists. It is largely used for dyeing; is fraudulently added to 
beers to render them bitter; and is of value in toxicological analysis, as 
it precipitates the alkaloids from their solutions. 

When taken internally in overdose, it acts as a poison; it may be 
separated from animal fluids or from beer by evaporating to a syrup, ex- 
tracting with 95 per cent, alcohol, acidulated with sulphuric acid; filter- 
ing; evaporating; and applying the above-mentioned tests to a solution 
of the residue. 



Cresylol. 

Cresol — Cresylic acid — Benzylic phenol — Cresylic phenol — C 6 H 4 (CH 3 ) 
OH — accompanies phenol in coal- and wood-tars, from which it may be 
obtained by fractional distillation; it is more readily obtained pure from 
toluene. 

When pure it is a crystalline solid, fusible at 34.5°; as usually met 
with, however, it is a liquid, which does not solidify at — 18°, and boils 
at 203°; it has an odor of creasote. Its properties, decompositions and 
products resemble those of phenol. 

Creasote is a complex mixture, containing phenol, cresylol, creasol, 
C 8 H 10 O 2 , and other substances obtained from wood-tar, and formerly ex- 
tensively used as an antiseptic. It is an oily liquid, colorless when 
freshly prepared, but becoming brownish on exposure to light; it has a 
burning taste and a strong, peculiar odor; its specific gravity is variously 
stated from 1.037 to 1.087 at 20°; it boils at 203°, and does not solidify at 
-27°. 

Crude phenol is often substituted for creasote; the two substances 
may be distinguished by the following characters: 



AROMATIC ALCOHOLS. 



323 



Phenol. 

Soluble in commercial glycerin. 
Precipitates nitro-celiulose from collodion. 
Gives a brown color with ferric chloride 

and alcohol. 
Gives a violet color with ferric chloride 

and ammonium hydrate. 



Creasote. 

Insoluble in commercial glycerin. 

Does not precipitate collodion. 

Gives a green color with ferric chloride 

and alcohol. 
Gives a green color, passing to brown, with 

ferric chloride and ammonium hydrate. 



Xenols — Xylenols — C 6 H 3 (CH 3 ) 2 OH. — Theoretically there are six pos- 
sible xenols, derivable from corresponding xylenes; of these, four have 
been thus far obtained by the general methods of obtaining the phenols. 
None is of practical interest. 

Thymol — Cymylic lohenol — C 6 H(CH 3 ) 4 OH, exists, accompanying cy- 
mene and thymene, C 10 H ]6 , in essence of thyme, from which it was first and 
is still obtained; the essence contains about one-half its weight of thymol, 
which is separated by agitation with a concentrated solution of caustic 
soda; separation of the alkaline liquid, which is diluted and neutralized 
with hydrochlorie acid; thymol separates and is purified by rectification 
at 230°. 

It crystallizes in large, transparent, rhombohedral tables; has a pep- 
pery taste and an agreeable, aromatic odor; it fuses at 44° and boils at 
230°; is sparingly soluble in water, very soluble in alcohol and ether; 
with the alkalies it forms definite compounds, which are very soluble in 
water. Its reactions are very similar to those of phenol. 

Thymol is an excellent disinfecting and antiseptic agent, and one of 
the best of embalming materials; possessing the advantage over phenol of 
having itself a pleasant odor, while that of phenol is disagreeable to 
most persons. 



Aromatic Alcohols. 



The alcohols corresponding to this series of hydrocarbons have the 
same composition as the corresponding phenols, from which they differ in 
constitution and in having the function of true alcohols (see p. 150). 
The first of the series is: 

Benzylic alcohol — Benzoic alcohol — Benzyl hydrate — C 6 H 5 (CH a 
OH) — does not exist in nature, and is of interest chiefly as corresponding to 
two important compounds, benzoic acid and benzoic aldehyde (oil of bit- 
ter almonds). It is obtained by the action of potassium hydrate upon oil 
of bitter almonds, or by slowly adding sodium amalgam to a boiling solu- 
tion of benzoic acid. 

It is a colorless liquid; sp. gr. 1.05 at 14.4°; boils at 206.5°; has an 
aromatic odor; is insoluble in water, soluble in all proportions in alcohol, 
ether, and carbon disulphide 

By oxidation it yields, first, benzoic aldehyde, C 6 H 5 (COH); and after- 
ward, benzoic acid, 6 H 5 (COOH). By the same means it may be made 
to yield products similar to those obtained from the alcohols of the satu- 
rated hydrocarbons. 

The remaining alcohols of this series are: 

Xylylic alcohol C 6 H 6 (CH 2 -C1I 2 0H). 

Cumylic alcohol C 6 H 5 (CH„-CH 2 -CH 2 0H). 

Cymylic alcohol C 6 H 5 (CH 3 -CH a -CH 2 -CH a OH). 



324 GENEEAL MEDICAL CHEMISTRY. 



Diatomic Aromatic Hydrates. 

There are three classes of these substances, viz. : Diatomic phenols, 
diatomic alcohols, and alphenols, which last are substances having a mixed 
function of alcohol and phenol, thus: 

H H H 



c 




C 




C 


H-C C-OH 


H- 


/\ 
-C C-CH 2 OH 


H- 


/\ 

-C C-CH 2 0H 


II 1 
H-C C-OH 


H- 


II 1 
-C C-CH 2 OH 


H- 


II 1 
-C C-OH 


c 

1 




c 




c 

1 


1 
H 




i 

H 




1 
H 


Hydroquinone 
(diatomic phenol). 




Toluyl glycol 
(diatomic alcohol). 




Saligenin 
(alphenol). 



Phenols — Oxyphenols. — There exist three different compounds of the 
composition C 6 H 6 2 . 

Pyrocatechin, a crystalline solid, fusible at 112°, boiling at 240°, has 
a powerful odor; soluble in water and alcohol; obtained by the dry dis- 
tillation of kino and catechu. 

Resorein, colorless, prismatic crystals, fusible at 110°, boiling at 
270°; obtained by the action of potash on galbanum, assafetida, etc. 

Hydroquinone, transparent, colorless prisms, fusible at 177.5°; solu- 
ble in water, alcohol, and ether; obtained by the action of reducing agents 
on quinone. 

/° 

Quinone, C 6 H 4 | — is formed by the action of oxidizing agents on 

quinic acid (q. v.); it crystallizes in long, transparent needles, fusible 
at 115.7°; very soluble in water, alcohol, and ether; very volatile, emitting 
irritating vapors at all temperatures; its solution stains the skin brown. 

Orcin, C 7 H 8 O ti , the superior homologue of hydraquinone, is obtained 
from lichens of the genus Mocella. It forms white, crystalline needles, 
fusing at 86°, boiling at 280° — 287°; sweet in taste; soluble in water, 
alcohol, and ether. Anhydrous orcine absorbs dry ammonia, forming large, 
colorless crystals, which, although permanent in a dry vacuum, rapidly 
absorb moisture from the air and are converted into orcein, C 7 H 7 N0 3 , the 
coloring matter of orchil and litmus. 

/CH 2 OH 

Saligenin, CH — is an alphenol, i.e., a substance partly 

\OH 
alcohol (by the group CH 2 OH) and partly phenol. It is obtained from 
salicine (q. v.) in large, tabular crystals; quite soluble in alcohol, water 
and ether. Oxidizing agents convert it into salicylic aldehyde, which by 
further oxidation yields salicvlic acid. 

/CH 2 OH 

Toluyl glycol, C 6 H 4 — the only one of the diatomic, 

\CH 2 OH 
aromatic alcohols at present known; has been recently obtained by Gri- 



ACIDS CORRESPONDING TO THE AROMATIC HYDRATES. 325 

maux, by saponifying the corresponding chloride or bromide; it forms 
opaque, crystalline needles; very soluble in water. By oxidation with 
potassium dichromate and sulphuric acid, it yields terephthalic acid. (See 
below.) 

Triatomic Aromatic Hydrates. 

The only compounds of this class at present known with certainty are 
two isomeric triatomic phenols, which probably owe the differences in 
properties existing between them to a different placing of the OH groups. 
They are phloroglucin and pyrogallol. 

Phloroglucin, C 6 H 3 (0H) 3 — is obtained by the action of potash upon 
phloretin, quercitrin, maclurin (see Glucosides), catechin, kino, etc. It 
crystallizes in rhombic prisms, containing 2 Aq. ; is very sweet; very sol- 
uble in water, alcohol, and ether. 

Pyrogallol — Pyrogallic acid — C 6 H 3 (OH) 3 — is formed when gallic acid 
(q. v.) is heated to 200°; it crystallizes in white needles; neutral in reac- 
tion; very soluble in water; very bitter; fuses at 115°; boils at 210°; 
poisonous. Jts most valuable property is that of absorbing oxygen from 
the air, for which purpose it is used in the laboratory in the form of a 
solution of potassium pyrogallate. 



Acids Corresponding to the Aromatic Hydrates. 

The acids, possibly derivable from benzene by the substitution of 
(COOH), or of (COOH) and (OH), for atoms of hydrogen, would form, were 
they all known, a great number of series; there are, however, compar- 
atively few of them which have been as yet obtained, although the num- 
ber of acid series known is greater than that of corresponding alcohols. 
Each series of mono- and diatomic alcohols furnishes a corresponding 
series of acids; thus: 



C,H-CH,OH 

Benzoic alcohol. 



C 6 H-COOH 

6 5 

Benzoic acid. 



Toluyl glycol. 

c n /COOH 
^ 6 ±1 4N N C00H 

Terephthalic acid. 



p n /CH 2 OH 

Saligenin. 

p R /COOH 

Salicylic acid. 



There are still a number of other series of acids possibly derivable 
directly from benzene, without speaking of substituted acids of more com- 
plex nature; of these, however, the majority are wanting. 

By the progressive substitution of groups (COOH) for atoms of hy- 
drogen in benzene, we may obtain six series of acids, five of which have 
been isolated: 



C 6 H 5 (COOH) -C n H 2n _ e O, Benzoic series. 

C 6 H 4 (COOH) 2 -C n H 2n _,„0 Phthalic series 



C 6 H 3 (COOH) 3 -C w H 2n _ 
C 6 H 2 (COOH) 4 -C„H 2n _ 
C 6 H(COOH) 6 -C„H 2n _ 
C 6 (COOH) 6 -C n H 2n _ 



6 Trimellitic series. 

8 Prehnitic series. 

O 10 Wanting. 

O Mellitic series. 



326 



GENERAL MEDICAL CHEMISTRY. 



The alphenols, containing a single group (OH), are at present repre- 
sented by a single series: 

C 6 H 4 (OH) (COOH)-C n H 2n _ 8 3 — Salicylic series. 

Corresponding to the unknown alphenols, containing a greater num- 
ber of (OH) groups, there are at present but two series of acids known: 



and 



C 6 H 3 (OH), (COOH)-C n H 2n _ 8 — Yeratric series, 
C 6 H 2 (OH), (COOH)-C n H 2n _ 8 6 — Gallic series. 



In each of these series the basicity is, as usual, equal to the number of 
groups (COOH). 



Benzoic Series, C n H 2M _ 8 O a . 

The acids of this series (which are, as the formula above indicates, 
monobasic) at present known are: 



Benzoic acid C 7 H O 

Toluic acid C g H B : 

Xylic acid C 9 H 10 O 2 



Cumic acid .Ci H 12 O 2 

a Cymic acid CiiHi 4 2 



Benzoic acid, C 6 H 6 (COOH) — one of the earliest known of organic 
acids, having been obtained by sublimation from benzoin. It exists ready 
formed in benzoin, toiu balsam, castoreum, and several resins (see p. 297), 
it does not exist in animal nature, so far as is at present known ; in those 
situations in which it has been found, it has resulted from decomposition 
of hippuric acid (q. v.), or has been introduced from without. When 
taken in moderate doses, it does not pass out in its own form, but is con- 
verted into hippuric acid; in excessive doses a portion is eliminated, un- 
changed, in the urine. 

Benzoic acid is obtained by one of two processes: 1st. For use in med- 
icine, it is extracted from benzoin, which is boiled for some hours with 
milk of lime; the solution of calcium benzoate so formed is filtered off 
and decomposed with hydrochloric acid; the precipitated acid is washed 
and purified, either by recrystallization from boiling water, or by sublima- 
tion; in the latter case the crude acid is heated in a porcelain dish, over 
which is placed a sheet of filter-paper, and over that a cone of bristol- 
board, which acts as a condenser. The process formerly followed, by direct 
sublimation of benzoin, is not as advantageous. 2d. For use in the arts, 
benzoic acid is obtained from the urine of herbivorous animals; this is 
boiled with hydrochloric acid, and treated with milk of lime, the calcium 
salt is decomposed, and the liberated acid purified as above. The acid 
prepared by this process retains tenaciously an odor of urine, which may 
be removed to a great extent by distilling with a little benzoin. 

Benzoic acid is formed in a variety of reactions, among others by syn- 
thesis from benzene; this is converted into its monobromo-derivative, 
which is mixed with sodium and treated with carbon dioxide: 



C„H 5 Br 

Monobromo- 

benzene. 



+ Na, + 



Sodium. 



co 2 = 


= C,H 5 2 Na 


+ 


NaBr 


Carbon 
dioxide. 


Sodium 
benzoate. 




Sodium 
bromide 



BENZOIC SEEIES. 327 

a general reaction, by which several other acids are obtained from corres- 
ponding hydrocarbons. 

Pure benzoic acid crystallizes in white, transparent, pearly plates or 
needles; odorless (the pharmaceutical product usually has a faint odor of 
benzoin); acid in taste; fuses at 122°; sublimes at 145°; boils at 240°; 
sparingly soluble in cold water, soluble in twelve parts of boiling water, 
very soluble in alcohol and ether. 

Dilute nitric and chromic acids do not attack benzoic acid. It dis- 
solves in ordinary sulphuric acid, and may be precipitated from the solu- 
tion, unchanged, by the addition of water; Nordhausen sulphuric acid 
converts it into sulpJiobenzoic acid. Fuming nitric acid forms with it 
nitrobenzoic acid/ and a mixture of fuming nitric and sulphuric acids 
binitrobenzoic acid. Under the influence of sodium amalgam, it yields 
benzylic alcohol and other products. Distilled with an excess of lime or 
baryta, it yields carbon dioxide and benzene. 

The salts of benzoic acid are all soluble, those of the heavy metals less 
so than those of the alkaline metals. 

The radical of benzoic acid (C 7 H 6 0)', is known as benzoyl; it enters 
into a number of compounds similar to those of acetyl (C u H 3 0)'; thus we 
have a hydride C 7 H 6 OH; a chloride, C 7 H 5 0C1; an amide, C 7 H & ONH 2 . 

Intimately connected with benzoic acid is Hippurie acid — Benzylgly- 
cocol — Benzyl-amido-acetic acid — C 9 H 9 N0 3 — a constant constituent of 
the urine of the herbivora. In human urine, with normal food, it exists in 
small quantity; with a purely vegetable diet, its elimination is greatly in-. 
creased, as it is also after the administration of benzoic acid, and, to a less 
degree, in diabetes mellitus and in chorea. The amount of hippurie acid 
eliminated under normal circumstances by man varies from 0.29 gram to 
2.84 grams in twenty-four hours. 

Hippurie acid is extracted from the urine of the horse, cow, etc.; this 
is concentrated to a syrup and treated with two to three times its bulk of 
hydrochloric acid; the highly colored deposit of hippurie acid is converted 
into sodium hippurate; the solution, decolorized with a little hypochlorite 
solution, and again precipitated with hydrochloric acid; if required pure, it 
must be further decolorized by boiling with animal charcoal, and recrystal- 
lization. 

It crystallizes in colorless, transparent prisms; odorless; faintly bitter; 
sparingly soluble in cold water, less so in the presence of hydrochloric 
acid, more so in the presence of hydrodisodic phosphate, very soluble in 
boiling water and in alcohol, insoluble in ether; fuses at 130°; boils at 
240°; at a slightly higher temperature it is decomposed, with formation of. 
benzoic and hydrocyanic acids. 

To understand the reactions of hippurie acid, a knowledge of its con- 
stitution is necessary. It has been long known that hippurie acid may 
be decomposed into glycocol (see page 2Q8) and benzoic acid. Later, by 
the action of nitrous acid upon hippurie acid, an acid having the constitu- 
tion of glycolic acid, in which the alcoholic hydrogen is replaced by 
benzoyl (see above) was obtained, and designated as benzoglycolic acid. 
Finally, hippurie acid has been obtained synthetically by the action of 
benzoyl chloride upon silver glycolamate: 



C 2 H 8 (NH,)0 5 Ag 


+ 


C 7 H 5 0C1 = 


= C„H,N0 3 


+ 


AgCl 


Silver glycolamate. 




Benzoyl 
chloride. 


Hippurie 
acid. 




Silver 
chloride. 



And again, hippurie acid has been obtained by the action of benzamide 



328 GENERAL MEDICAL CHEMISTRY. 

upon chloracetic acid. Now, glycocol is derivable from glycolic acid by 
the substitution of NH U for OH; or from chloracetic acid by the substitu- 



tion of NH a for CI: 






CH a OH 


CH a Cl 


CH,(NHJ 


COOH 


COOH 


COOH 


Glycolic acid. 


Chloracetic acid. 


Amido-acetic acid (glycocol) 



The foregoing decompositions and syntheses show that hippuric acid 
is glycocol in which the radical benzoyl has been substituted for one H of 
the group NH 3 ; it is therefor: 

CH, (NH [C.H.O] ) 

COOH 

Benzyl-glycocol or benzyl amido-acetic acid. 

Hippuric acid dissolves unchanged in concentrated hydrochloric acid; 
on boiling the solution it is decomposed into benzoic acid and glycocol; 
the same decomposition is effected by dilute sulphuric, nitric, and oxalic 
acids, and also by a ferment developed in putrefying urine. Concentrated 
sulphuric acid forms a brown solution with hippuric acid, which, on the 
application of heat, gives off sulphur dioxide and benzoic acid. Nascent 
hydrogen produces a number of derivatives from hippuric acid, among 
which are benzoic aldehyde and glycocol. Oxidizing agents convert it 
into benzoic acid, carbon dioxide, and benzamide. 

The determination of hippuric acid in urine is a tedious process. 
About a litre of the urine is precipitated with baryta water; filtered; the 
excess of barium removed from the nitrate by cautious addition of sul- 
phuric acid, avoiding an excess; the filtrate is neutralized with hydro- 
chloric acid and evaporated to a syrup; this is extracted with alcohol; 
the alcoholic solution decanted and evaporated over the water-bath ; the 
residue repeatedly washed with ether; dissolved in warm water and 
heated with a little milk of lime; filtered, the nitrate decomposed with 
hydrochloric acid; the crystals which separate are washed with a small 
quantity of water, dried, and weighed. It is usually necessary to redis- 
solve the acid in water, decolorize with animal charcoal, and reprecipitate 
before weighing. 

The characters of hippuric acid are: 1st, when heated in a dry tube, it 
fuses and decomposes, giving a sublimate of benzoic acid and an odor of 
hydrocyanic acid (q. v.); 2d, it gives a brown precipitate with ferric 
salts (so do benzoic and succinic acids); 3d, when heated with lime, it 
gives off benzene and ammonia. Benzoic acid, by similar treatment, 
gives off benzene, but no ammonia. 

The remaining acids of the benzoic series are not of medical interest. 
The number of their isomeres is great. 



Phthalic Series, C n H 2n _ ]0 O 4 . 

Phthalic acid, C 8 H 6 4 , and its isomeres, terephthalic and isophtha- 
lic acids, are the only ones of this series at present known. Phthalic 
acid is obtained by the action of nitric acid upon naphthalene or alizarin 



TRIMELLITIC SEEIES. 329 

(q. v.). It crystallizes in white prisms; sparingly soluble in water, very 
soluble in alcohol and ether; it fuses at 180°, and at a higher temperature 
is decomposed into phthalic anhydride, 6 H 4 (CO) 2 O, and water; by cau- 
tious heating it is decomposed into carbon dioxide and benzoic acid, a 
reaction which is utilized to obtain the last-named acid. 



Salicylic Series, CJB 2n _ 8 3 . 

The acids of this series (which are, as indicated by the formula on p. 
325, partly phenols, partly acids) are the following: 



Salicylic acid C 7 H 6 3 

Anisic acid C f H b 3 

Phloretic acid C 9 Hi O 3 



Oxycuminic acid CioH lv O s 

Thymotic acid C11H14O3 



Salicylic Acid — Oxybenzoic acid — C 6 H 4 (OH) COOH — was first ob- 
tained from essence of spiroea, which consists largely of salicylic alde- 
hyde, and subsequently from oil of wintergreen (gault/ieria), which 
contains methyl salicylate; and also from salicine, a glucoside yielding 
salicylic aldehyde. 

At present salicylic acid is obtained almost exclusively by Kolbe's 
method, from phenol. This is fused, and while a current of dry carbon 
dioxide is passed through it, small portions of sodium are added; the so- 
dium salicylate thus formed is dissolved in water and decomposed with 
hydrochloric acid, when the liberated salicylic acid is precipitated. 

It crystallizes in fine white needles (the pharmaceutical product is 
usually pink); very sparingly soluble in cold water, quite soluble in hot 
water, alcohol, and ether; it fuses at 158°, and may be distilled with but 
slight decomposition, if it be pure. 

Chlorine and bromine form with it products of substitution. Fuming 
nitric acid forms with it a nitro-derivative and, if the action be prolonged, 
converts it into picric acid. With ferric chloride, its aqueous solution as- 
sumes a fine violet color. 

Salicylic acid and its salts (it is monobasic, although diatomic) are ex- 
tensively used in medicine, both externally as antiseptics and internally 
in the treatment of rheumatism, etc. It is not without caustic properties, 
and hence, when taken internally, it should be largely diluted. 



Trimellitic Series, C n H 2n _ 12 6 . 

There are no less than three isomeric acids having the composition of 
the first term of this series, all of which are tribasic: 

Trimellitic acid, C 6 H 3 (COOH) 3 — obtained by heating hydropyromel- 
litic acid with sulphuric acid, isophthalic acid being formed at the same 
time; also formed when rosin is oxidized with nitric acid. Fuses at 216°. 

Trimesitic acid — formed by the oxidation of mesitylenic acid / fuses 
at a temperature above 300°. 

JTemimellitic acid — formed, along with phthalic acid, by heating hy- 
dromellophanic acid with sulphuric acid; fuses at 185°. 



330 GENERAL MEDICAL CHEMISTRY. 



Prehnitic Series, CJEI in _ 14 8 . 

Of this series there are also three isomerides of the first term; all te- 
trabasic : 

Prehnitic acid, C 6 H 2 (COOH) — fuses at 237°. 

JPyromellitic acid — formed by the distillation of mellitic acid. 

Mellophanic acid — obtained, along with prehnitic acid, by decompos- 
ing hydromellitic acid, C 12 H 12 12 . 



Mellitic Series, C n H 2n _ 18 13 , 

is represented by a single term, in which the hydrogen of benzene has 
been entirely replaced: 

Mellitic acid, C 6 (COOH) 6 — occurs in nature as its aluminium salt in 
the mineral called mellite or honey stone. It has also been obtained syn- 
thetically by oxidizing charcoal with potassium permanganate in alkaline 
solution. 

It crystallizes in colorless needles, readily soluble in water; sour in 
taste. It withstands the action of reagents well, but by distillation with 
quicklime is decomposed into benzene and carbon dioxide. 



Gallic Series, C n H 2n _ 8 5 . 

Gallic acid, C 6 H 2 (OH) 3 COOH — the first term and only representa- 
tive of the series, exists in nature in certain leaves, seeds, and fruits. It 
is best obtained from g&ll-nuts which contain its glucoside, gallotannic 
acid (q. v.). These galls are moistened and kept at a temperature of 20° 
— 25°, being moistened from time to time, for a month; the colored, 
mouldy mass is strongly expressed and the residue extracted with boiling 
water, which, on cooling, deposits crystals of gallic acid. It can be ob- 
tained from salicylic acid. 

It crystallizes in long, silky needles; odorless; acidulous in taste; 
sparingly soluble in cold water, very soluble in hot water and in alcohol; 
its solutions are acid. When heated to 210° — 215° it yields carbon diox- 
ide and pyrogallol (q. v.). Its solution does not precipitate gelatin, nor 
the salts of the alkaloids, as does tannin. It forms four series of salts. 



Aldehydes. 

Benzoic aldehyde — Benzoyl hydride — C 6 H S (COH) — is the main 
constituent of oil of bitter almonds, although it does not exist in the al- 
monds (see p. 342) ; it is formed, along with hydrocyanic acid and glucose, 
by the action of water upon amygdalin. It is also formed by a number 
of general methods of producing aldehydes: by the dehydration of ben- 
zylic alcohol; by the dry distillation of a mixture in molecular propor- 
tions of calcium benzoate and formiate; by the action of nascent hydro- 
gen upon benzoyl cyanide, etc. 

It is obtained from bitter almonds; these are crushed and freed from 



ALDEHYDES. 331 

fixed oil by expression; the cake is mixed with a large quantity of water, 
in which it remains twenty-four hours, after which the mixture is dis- 
tilled by steam heat as long as the distillate has the odor of bitter al- 
monds; the oil separates from the watery liquid, which still contains a 
considerable quantity in solution, recoverable by a second distillation. 
This crude oil contains, besides benzoic aldehyde, hydrocyanic and ben- 
zoic acids and cyanobenzoyl; to purify it, it is treated with three to four 
times its volume of a concentrated solution of sodium bisulphite; the 
crystalline mass is expressed, dissolved in a small quantity of water, and 
decomposed with a concentrated solution of sodium carbonate — the treat- 
ment being repeated, if necessary. 

It is a colorless oil, having an acrid taste and the odor of bitter almonds; 
sp. gr. 1.043; boils at 179.4°; soluble in thirty parts of water, and in all 
proportions in alcohol and ether. 

Its vapor, passed through a tube filled with fragments of pumice and 
heated to redness, is decomposed into benzene and carbon dioxide. Oxi- 
dizing agents convert it into benzoic acid, a change which occurs by 
mere exposure to air. Nascent hydrogen converts it into benzylic alco- 
hol. With chlorine or bromine it forms benzoyl chloride or bromide. 
Sulphuric acid dissolves it when heated, forming a purple-red color, which 
turns black if more strongly heated. 

When perfectly pure, benzoic aldehyde exerts no deleterious action 
when taken internally; owing, however, to the difficulty of completely re- 
moving the hydrocyanic acid, the substances usually sold as oil of bitter 
almondsy ratafia, and almond flavor, are almost always poisonous, if taken 
in sufficient quantity. They may contain as much as ten to fifteen per 
cent, of hydrocyanic acid, although said to be "purified"; the presence 
of the poisonous substances may be detected by the tests given on page 
340. 

Cuminic aldehyde, CgH^ (COH), exists, along with a liquid hydro- 
carbon, in cumin-seeds and essence of cumin, from which it is obtained, 
by fractional distillation, in much the same way as benzoic aldehyde. It 
is a colorless or yellowish oil; has a penetrating and disagreeable odor, and 
an acrid, burning taste; sp. gr. 0.9727 at 13°; boils at 220°. Its reactions 
are similar to those of benzoic aldehyde. 

Salicylic aldehyde — Salicyl hydride — Salicylol — Salicylous acid — 
C 6 H 4 (OH) COH — exists in the flowers of spirce ulmaria, and is the prin- 
cipal ingredient of the essential oil of that plant. It is best obtained by 
oxidizing salicine (q. v.) with a mixture of sulphuric acid and potassium 
dichromate. 

It is a colorless oil; turns red on exposure to air; has an agreeable, 
aromatic odor, and a sharp, burning taste; sp. gr. 1.173 at 13.5°; boils at 
196.5°; soluble in water, more so in alcohol and ether. 

It is, as we should suspect from its origin, a substance of mixed func- 
tion, possessing the characteristic properties of aldehyde and phenol. It 
produces a great number of derivatives, some of which have the charac- 
ters of salts and ethers. 

Anisic aldehyde, C 6 H 3 CH 3 (OH) COH — obtained from the essence 
of anis; is a yellowish liquid; has an aromatic odor and a burning taste; 
sp. gr. 1.09 at 20°; boils at 254°; almost insoluble in water, readily soluble 
in alcohol and ether. 



332 



GENERAL MEDICAL CHEMISTRY. 



Amines. 

Phenylamines. 

Benzene may be considered as being made up of a radical group 
(C 6 H B )', united to hydrogen; this radical is known as phenyl, and benzene 
is, therefor, phenyl hydride, as marsh-gas is methyl hydride. The radi- 
cal, phenyl, is capable, like methyl, of replacing atoms of hydrogen of 
ammonia to form amines precisely similar in typical constitution to those 
of the univalent alcoholic radicals (see p. 155); or these amines may be 
considered as formed by the substitution of a group NH 2 for an atom of 
hydrogen of one molecule of benzene, or of (NH)" for two atoms of 
hydrogen in two molecules, etc. : 

H 



CH 2 (NH 3 )' 
GET 





/ \ 

H-C C-NH S 

I II 

H-C C-H 

v 



i 



H-C 

I 
H-C 



H 



H 

I 
C 



N 



N 



\ 



\ 



c 



C 



/ 



c 



C-HH-C 



H 



C 



\ 



X c 7 

I 
H 



C-H 

II 
C-H 



or typically: 




(C.H.)' , 
H ! 

H 

Phenylamine. 



(O.H.)' , 

(O.HJ' } 
H 

Diphenylamine. 



These amines are, in their turn, capable of forming a vast number of 
products of substitution, salts, etc. Of the compounds of this class, the 
most important by far is: 

Phenylamine — Aniido - benzene — Amido - benzol — Aniline — Kyanol 

— Cristalline — 6 tt 5 J- N. — It was discovered in 1826, by Unverdorben, 
among the products of the dry distillation of indigo; later it was found 



AMINES. 333 

to exist in coal-tar; and, finally, Zinin discovered the method of obtaining 
it from nitro-benzene which is at present used. This reaction is a reduc- 
tion, consisting in the removal of O a , and the substitution therefor of H a : 

0„H 5 (NO,) + 8H, = C 6 H 5 (NH S ) + 2H s O 

Nitrobenzene. Hydrogen. Amidobenzene. Water. 

Aniline is now obtained in large quantities from nitrobenzene, which 
is mixed with acetic acid, and to the mixture iron turnings or borings are 
gradually added; the nascent hydrogen liberated by the action of the 
metal upon the acid being the reducing agent; the addition of iron is 
continued until a pasty mass is formed, which is then neutralized with 
lime and subjected to distillation. 

Aniline is also formed in other reactions: in small quantity when 
phenol and ammonia are long heated together under pressure; by the dry 
distillation of indigo, etc. 

When pure, aniline is a colorless liquid; has a peculiar, aromatic 
odor, and an acrid, burning taste; sp. gr. 1.02 at 16°; boils at 184.8°; 
crystallizes at — 8°; soluble in thirty-one parts of cold water, soluble in 
all proportions in alcohol, ether, carbon disulphide, etc.; when exposed 
to air, it turns brown, the color of the commercial " oil," and, finally, 
resinifies; it is neutral in reaction. 

Its vapor, when heated to redness, is decomposed into carbon, am- 
monia, ammonium cyanide, and a complex brown liquid. Oxidizing agents 
convert it into blue, violet, red, green, or black derivatives. Chlorine, bro- 
mine, and iodine act upon it violently to produce products of substitu- 
tion. Concentrated sulphuric acid converts it, according to the conditions, 
into sulphanilic or disidphanilic acid. With acids it unites, after the 
manner of the ammonias, without liberation of water or hydrogen to 
form salts, most of which are crystallizable, soluble in water, and colorless, 
although by exposure to air, especially if moist, they turn red. 

The presence of aniline may be detected by the following characters: 
1st, on the addition of a nitrate and of sulphuric acid, a red color is pro- 
duced; 2d, cold sulphuric acid does not color it alone, on the addition of 
potassium dichromate, a fine blue color is produced, which, on dilution 
with water, passes to violet, and, if not diluted, to black (see Strychnine); 
3d, with calcium hypochlorite solution it gives a violet color; 4th, when 
heated with cupric chlorate, a deep black color is produced; 5th, a deep 
crimson color appears when it is heated with mercuric chloride. 

Experiments upon animals show aniline to be an active poison when 
taken in the liquid form, or by inhalation of its vapor; its salts, however, 
if pure, seem to be without deleterious action. The symptoms produced 
by aniline are very similar to those of nitrobenzene poisoning. 

Derivatives of aniline. — Although aniline and most of its salts are 
colorless, some of the most brilliant dyes at present in use are produced 
from them. We merely mention the more prominent: 

Hosaniline chloride — fuchsine — magenta — a magnificent red dye, for- 
merly obtained by oxidizing aniline with arsenic acid and combining the 
base so formed with hydrochloric acid. The difficulty of disposing of the 
arsenical refuse of this process, and the deleterious action of the dyes 
from which the arsenic had been imperfectly removed, have led to a 
modification of the process in which nitrobenzene itself is used as the 
oxidizing agent. The base, rosaniline, is an almost colorless, crystalline 
compound, although its salts are so brilliantly colored. 



334 GENERAL MEDICAL CHEMISTRY. 

The dyes derived from rosaniline are very numerous; prominent 
among them are fuchsine, rosaniline chloride, a green, crystalline sub- 
stance, soluble in alcohol, with a beautiful magenta color; Hofmann's 
violet, triethyl-rosaniline, obtained by heating together rosaniline and 
ethyl iodide; Lyons blue, triphenyl-rosaniline hydrochloride, obtained by 
heating rosaniline with an excess of aniline; gas green, obtained by 
heating rosaniline chloride with aldehyde and sulphuric acid; Paris 
violet, obtained by the oxidation of methyl aniline. 

Mauvein is a base whose sulphate, obtained by mixing cold dilute 
solutions of potassium dichromate and aniline sulphate, is a fine, purple 
dye. A blue dye is also obtained by heating mauvein with aniline. 

Aniline black is obtained by acting on aniline with a mixture of cu- 
pric sulphate and potassium chlorate. 

Saffronin is a base derived from commercial oils, rich in the superior 
homologues of aniline (toluidines); its hydrochlorate is largely used in 
place of samower for dyeing silks. 



SIXTH SERIES OF HYDROCARBONS. 

CJ3 2n _ 8 . 

This series has at present but two representatives, derivable from 
benzene by the substitution of one lateral chain for an atom of hydrogen. 

Cinnamene — Styrolene — Cinnamol — Styrol — Liquid essence of sty- 
rax — C 8 H 8 — exists ready formed in essential oil of styrax; it is also 
formed by decomposition of cinnamic acid (q. v.), or, synthetically, by the 
action of a red heat upon pure acetylene, a mixture of acetylene and ben- 
zene, or a mixture of benzene and ethylene. 

It is a colorless liquid; has a penetrating odor, recalling those of ben- 
zene and naphthalene, and a peppery taste; sp. gr. 0.928 at 16°; boils at 
143°; soluble in all proportions in alcohol and water; neutral in reaction. 

Cedrene, C 16 H 24 — is the liquid hydrocarbon of essence of Virginia 
cedar; it is a colorless liquid, of sp. gr. 0.984 at 14.5°, and boils at 237°. 



Alcohols — Series C n H 2n _ 8 0. 
There are but two alcohols of this series known : 
Cinnyl alcohol C 9 H 10 O ] Cholesterin C 2B H 44 

Cinnyl alcohol— Cinnamic alcohol — Styrolic alcohol — Styrone — 
Styraco7ie — Peruvine— C 9 H 9 OH — is obtained by distilling styracine (see 
below) with a concentrated solution of potash or soda» 

It crystallizes in soft, silky needles; has a sweet taste and an odor of 
hyacinth; fuses at 33°; distils at 250°; sparingly soluble in water, and 
readilv soluble in alcohol, ether, and cinnamene. 

Styracine, or cinnyl cinnamate, exists in Peru balsam and in styrax, 
from the latter of which it is obtained. 

It crystallizes in prisms, grouped in bundles; odorless and tasteless; 
fuses at 38°; insoluble in water> sparingly soluble in cold alcohol, 



ALCOHOLS. 335 

readily soluble in ether. When heated with potash it is decomposed, 
liberating cinnamic alcohol. 

Cholesterie alcohol — Cholesterin — C 26 H 43 OH. — This substance, of 
great physiological interest, is shown by its reactions to be certainly an 
alcohol, and probably one belonging to this series; although it is usually 
classed by physiologists among the fats for no better reason than that it 
is greasy to the touch and soluble in ether. 

It has been found in the animal economy, normally in the bile, blood 
(especially that coming from the brain), nerve-tissue, brain, spleen, sebum, 
contents of the intestines, meconium and faeces; pathologically in biliary 
calculi, in the urine in diabetes and icterus, in the fluids of ascites, hy- 
drocele, etc., in tubercular and cancerous deposits, in cataracts, in ather- 
omatous degenerations, and sometimes, in masses of considerable size, in 
certain cerebral tumors. It has also been found to exist in the vegetable 
world in peas, beans, olive-oil, wheat, etc. It has not been obtained by 
synthesis. 

Cholesterin is best obtained from biliary calculi, the lighter-colored 
varieties of which consist almost entirely of this substance. The calculi 
are pulverized, extracted with boiling ether, the solution filtered hot, 
the ether distilled off, the residue dissolved in boiling alcohol, and the 
solution allowed to cool; the crystals which separate are heated for some 
time with alcohol containing a little potash; on cooling, crystals form, 
which are finally washed with alcohol so long as the washings are colored 
or alkaline, and recrystallized from ether. 

Cholesterin crystallizes with or without water of crystallization; from 
benzol, petroleum, chloroform, or anhydrous ether, it separates in delicate, 
colorless, silky needles, having the composition C 26 H 44 0; from hot alcohol, 
or a mixture of alcohol, and ether, it crystallizes in rhombic plates, usually 
with one obtuse angle wanting, having its composition C 26 H 44 + 1 Aq. ; 
these crystals, transparent at first, become opaque on exposure to air, 
from loss of aq. It is insoluble in water, in alkalies and dilute acids, 
difficultly soluble in cold alcohol, readily soluble in hot alcohol, ether, 
benzol, acetic acid, glycerin, and solutions of the biliary acids. It is 
odorless and tasteless. When anhydrous it fuses at 145° and solidifies 
at 137°; at 360° in vacuo it distils unchanged; sp. gr. 1.046. It is las- 
vogyrous, [a] D = 31.6° in any solvent. 

It combines readily with the volatile fatty acids. From its solution 
in glacial acetic acid a compound having the composition C 2fl H 44 0,C 2 H 4 2 
separates in fine curved crystals, which are decomposed on contact with 
water or alcohol; when heated with acids under pressure, it forms true 
ethers. Hot nitric acid oxidizes it to cholesterie acid, C 8 H 10 O 5 , which is 
also produced by the oxidation of biliary acids; a fact which indicates 
the probable existence of some relation between the methods of forma- 
tion of cholesterin and of the biliary acids in the economy. 

Cholesterin may be recognized by the following reactions: 1st, moist- 
ened with concentrated nitric acid and evaporated to dryness, a yellow 
residue remains, which turns brick-red (not bright red, as in the case of 
uric acid) on the addition of ammonium hydrate; 2d, it is colored violet 
when a mixture of two volumes sulphuric or hydrochloric acid, and one 
volume ferric chloride solution is evaporated upon it; 3d, when ground 
up with sulphuric acid and chloroform added, a blue-red or violet color is 
produced, which passes into green on exposure to air. 



336 GENERAL MEDICAL CHEMISTRY. 



Acids — Series C w H 2n _ 10 O 3 . 

Cinnamic acid, C 8 H 7 ,COOH — exists in syrax, and in Peru and 
Tolu balsams; it is also formed by the oxidation of cinnyl alcohol; by the 
action of potassium hydrate an essence of cinnamon; and by heating 
together acetyl chloride and benzoyl hydride under pressure. 

It forms prismatic crystals; sp. gr. 1.195; fuses at 137°; boils at 293°; 
quite soluble in cold water and ether. 

Cinnamic aldehyde, C 8 H 7 ,COH — is one of the constituents of 
essence of cinnamon. It is a colorless oil; denser than water; turns brown 
rapidly on exposure to air, from which it also absorbs oxygen and is 
converted into cinnamic acid. 



SEVENTH SERIES OF HYDROCARBONS. 

The only representative of this series at present known is 
Naphthydrene — Naphthylene hydride — C lo H 10 — a substance having 
only theoretical interest, obtained by heating naphthalene with potassium, 
and decomposing the product with water. It also occurs in heavy petro- 
leum. It is a colorless liquid; boils at 205°, and has a strong, disagreeable 
odor. 

EIGHTH SERIES OF HYDROCARBONS. 

The only term of this series is 

Naphthalene, C 10 H 8 — discovered in 1820 in coal-tar. It has been 
formed by an interesting synthesis which indicates its constitution; ben- 
zene and ethylene, when heated together, unite to form, first, cinnamene 
(q. v.), and afterward naphthalene. It is constituted by the fusion of two 
benzol groups by two carbon-atoms, thus: 



H H 

I 




i 



H-C C C-H 
H-C C C-H 



\/ 

c c 

I I 

H H 

It is obtained in considerable quantities from coal-tar, by fractional 
distillation, and is used for the production of a number of brilliant dyes. 

It crystallizes in large, brilliant plates; has a burning taste and a faint 
aromatic odor; fuses at 80° and boils at 217°, subliming, however, at a 



ELEVENTH SERIES OF HYDROCARBONS. 337 

temperature much below its boiling-point; sp. gr. 1.158 at 18°; it burns 
with a bright, but very smoky flame; is insoluble in cold water, very 
sparingly soluble in boiling water, readily soluble in alcohol, ether, and 
essences. 

Chlorine, bromine, nitric acid, and concentrated sulphuric acid attack 
it to form substitution compounds. Alkalies do not affect it. Nitric 
acid after a time oxidizes it to phthalic acid. 

Although many of the derivatives of naphthalene, which are very numer- 
ous, are of great chemical and industrial interest, they do not call for fur- 
ther mention here. 



NINTH SERIES OF HYDROCARBONS. 

Is also represented by a single hydrocarbon, derived from naphthalene. 

Acenaphthalene, C 12 H 10 — is produced synthetically by continuing 
the heating of naphthalene with ethylene, the reaction occurring in three 
steps. 

It also exists in coal-tar, from that portion of which, distilling at 270° 
— 290°, it is best obtained. 

It is only of theoretical interest. 



TENTH SERIES OP HYDROCARBONS. 

Is represented by two terms: Fluorene, a solid, crystalline body, boil- 
ing at 305°, obtained from coal-tar; and Stilbene, obtained by the action of 
ammonium sulphydrate upon an alcoholic solution of benzoic aldelhyde. 

ELEVENTH SERIES OF HYDROCARBONS. 

Ly n li 2n _ ]8> 

Anthracene, C 14 H 10 , is a substance which, although of but little 
medical interest, has assumed considerable importance in the arts and in 
chemical philosophy. 

It exists as a constituent of coal-tar, and is obtained by expression 
from the substance remaining in the still after the distillation of naphtha- 
lene, etc. The commercial product thus obtained is a yellowish mass 
containing from fifty per cent, to eighty per cent, of anthracene, the puri- 
fication of which is a matter of considerable difficulty. It has also been 
obtained synthetically. 

When pure, anthracene crystallizes in rhombic tables having a bluish 
fluorescence; fusible at 210° and boiling above 360°; its best solvents are 
benzene and carbon disulphide, in which, however, it is only sparingly 
soluble. 

Anthracene forms a number of products of substitution;. the only one 
of which we will mention is 
22 



338 GENEKAL MEDICAL CHEMISTRY. 

Alizarin, C 14 H 8 4 — a coloring matter now prepared on a large scale 
from anthracene, formerly only obtained from madder, and very exten- 
sively used in dyeing. As napthalene is formed by the condensation of 
two molecules of benzene, anthracene is constituted by the condensation 
of three; the constitution of anthracene and the relation of alizarin to it 
are shown by the formulae: 

H H H H 



c 




C C 


•\/\ 

H-C C 0-H 




x\/\ 

H-C C C-0 


1 II 1 
H-C C 0-H 




1 II 1 1 
H-C C C-O 


C 




c c 


/ X 
H-C C-H 


H- 


/ \ 

-O-C C-O-H 


\ S 

c-c 

1 1 




C-C 

1 1 


1 1 
H H 




1 1 

H H 


Anthracene. 




Alizarin. 



HIGHER SERIES OF HYDROCARBONS. 

The twelfth series is not at present represented. Of the thirteenth 
series, one hydrocarbon, pyrene, 16 H 10 , is known; and one of the fourteenth 
series, chrysene, C 1S H 12 , both obtained from coal-tar; the former fusing at 
142°, the latter at 230°— 235°. 



CYANOGEN COMPOUNDS. 

The substances which we have considered are all derivable, more or 
less directly, from the various hydrocarbons, and may be considered, upon 
the theory of types, to be formed by the substitution of radicals composed 
of carbon and hydrogen, carbon and oxygen, or carbon, hydrogen and 
oxygen, for atoms of hydrogen of the three typical substances, hydrogen, 
water, and ammonia. There are a number of very important substances 
which are typically considered as containing the radical (C„N)', which 
radical, known as cyanogen, possesses the same power of passing un- 
changed from compound to compound, as do methyl and ethyl, like which, 
also, it is incapable of separate existence. The substance sometimes 
known as cyanogen is not CN, but 



Dicyanogen (CN) 3 . 

This body is prepared by heating mercury cyanide in a small retort 
and collecting the gaseous product over mercury. 

Dicyanogen is a colorless gas, has a pronounced odor of bitter 
almonds; under a pressure of 4 atm. at 25° it is liquefied; sp. gr. 1.8064 A.; 



HYDROGEN CYANIDE. 



339 



it burns in air with a purple flame, giving off nitrogen and carbon dioxide. 
It is quite soluble in water ; the solution on exposure to air turns 
brown; with water alone, or with water and ammonia, dicyanogen enters 
into combinations which show the relations existing between the cyanogen 
compounds and others previously considered: 



(CN), + 4H 3 

Dicyanogen. Water. 



(CN), + 

Dicyanogen. 



H„0 = 



Water. 



= 0,O ( (NH ( ), 

Ammonium oxalate. 

CNOH + CNH 

Cyanic acid. Hydrocyanic acid. 



CNOH + H a O 

Cyanic acid 



NH. 



+ CO, 



id. 


Water. 


Ammonia. Carbon dioxide 


CNOH 

Cyanic acid. 


+ NH, 

Ammonia. 


= CON 2 H 4 

Urea. 



It has a very deleterious action upon both animal and vegetable life, 
even when largely diluted with air. 



Hydrogen Cyanide. 



CN 



Cyanogen hydride — Hydrocyanic acid — Prussic acid — tj [■ — exists 

ready formed in the juice of cassava, and is formed by the action of water 
upon bitter almonds, cherry-laurel leaves, etc. It is also formed in a great 
number of reactions: by the passage of the electric discharge through a 
mixture of acetylene and nitrogen; by the action of chloroform on am- 
monia; by the distillation or the action of nitric acid upon many organic 
substances; by the decomposition of cyanides. 

It is always prepared by the decomposition of a cyanide, although the 
nature of the cyanide and of the decomposing agent differ in the process 
advised by different authors, and according as the product is required 
pure or in dilute solution. Its preparation in the pure form is an opera- 
tion attended with the most serious danger, and should only be attempted 
by those well trained in chemical manipulation. For medical uses a very 
dilute acid is required; the acid. dil. hydrocyanicum (U. S., Br.) con- 
tains, if freshly and properly prepared, two per cent, of anhydrous acid; 
that of the French Codex is much stronger — ten per cent. 

The pure acid is a colorless, mobile liquid, has a penetrating and 
characteristic odor; sp. gr. 0.7058 at 7°; crystallizes at —15°; boils at 
26.5°; is rapidly decomposed by exposure to light. The dilute acid of 
the United States Pharmacopoeia is a colorless liquid, having the odor of 
the acid; faintly acid, the reddened litmus returning to blue on exposure 
to air; sp. gr. 0.997; ten grams of the acid should be accurately neutral- 
ized by 1.27 grams of silver nitrate. The dilute acid deteriorates on ex- 
posure to light, although more slowly than the concentrated; a trace of 
phosphoric acid added to the solution retards the decomposition. 

An acid of the medicinal strength may be obtained extemporaneously 
from argentic cyanide (q. v.); 9.925 grains of the pure, dry, salt are added 
to a mixture of 8.3 grams of hydrochloric acid of sp. gr. 1.16 made up to 
98 c.c, with distilled water; the resulting liquid, after agitation, is fil- 
tered from the precipitated silver chloride. A disadvantage of this method 



340 GENERAL MEDICAL CHEMISTRY. 

is that while an excess of silver nitrate is undesirable, an excess of hydro- 
chloric acid rapidly decomposes hydrocyanic acid, with formation of am- 
monium chloride and formic acid; the neutralization must therefor be most 
accurate, a result not readily attained in practice. The acid known as 
ScheeWs contains five per cent, of true acid. 

Most powerful acids decompose hydrocyanic acid quickly; the alka- 
lies enter into double decomposition with it to form cyanides' chlorine 
and bromine decompose it, with formation of cyanogen chloride and bro- 
mide; nascent hydrogen converts it into methylamine. 

The presence of hydrocyanic acid or of a soluble cyanide is recognized 
by the following characters: 1st, with silver nitrate a dense, white precip- 
itate is formed; the precipitate is not redissolved on the addition to the 
liquid of a small quantity of nitric acid, but is dissolved if separated and 
heated with concentrated nitric acid; it is but sparingly soluble in am- 
monia; freely soluble in solutions of alkaline cyanides or hyposulphites. 
2d, when treated with a solution of ammonium sulphydrate, and a solu- 
tion of ferric chloride added, a blood-red color is produced. 3d, on the 
addition of potassium hydrate, and subsequently of a mixture of ferrous 
and ferric sulphates, a greenish precipitate is formed, which is partly re- 
dissolved by hydrochloric acid, leaving a deep blue color. 4th, a dilute 
solution of picric acid produces a blood-red color when heated with a cy- 
anide and subsequently cooled. 

Toxicology. — Hydrocyanic acid is a violent poison, whether it be in- 
haled as vapor or swallowed, either in the form of dilute acid, of soluble 
cyanide, or of the pharmaceutical preparations containing it, such as oil 
of bitter almonds and cherry-laurel water, its action being more rapid 
when taken by inhalation or in aqueous solution than in other forms. 
When the medicinal acid is taken in poisonous dose, its lethal effect may 
seem to be produced instantaneously; nevertheless, several respiratory 
efforts usually are made after the victim seems to be dead, and instances 
are not wanting in which there was time for considerable voluntary motion 
between the time of the ingestion of the poison and unconsciousness. In 
the great majority of cases the patient is either dead or fully under the in- 
fluence of the poison on the arrival of the physician, who should, however, 
not neglect to apply the proper remedies if the faintest spark of life remain. 
Chemical antidotes are, owing to the rapidity of action of the poison, of 
no avail, although possibly chlorine, recommended as an antidote by many, 
may have a chemical action on that portion of the acid already absorbed. 
The treatment indicated is directed to the maintenance of respiration; 
cold douche, galvanism, artificial respiration until elimination has removed 
the poison. If the patient survive an hour after taking the poison, the 
prognosis becomes very favorable; in the first stages it is exceedingly 
unfavorable, unless the quantity taken has been very small. 

In cases of death from hydrocyanic acid a marked odor of the poison 
is almost always observed in the apartment and upon opening the body, 
even several days after death. In cases of suicide or accident, the vessel 
from which the poison has been taken will usually be found in close 
proximity to the body, although the absence of such vessel is not proof 
that the case is one of homicide. 

The presence of hydrocyanic acid may be readily detected in the body 
after death, and, notwithstanding the volatility and instability of the 
poison, its presence has been detected two months after death, although 
the chances of separating it are certainly the better the sooner after 
death the analysis is made. The search for hydrocyanic acid is combined 



METALLOCYANIDES. 841 

■with that for phosphorus (see p. 109); the part of the distillate contain- 
ing the more volatile products is examined by the tests given above; it 
is best, when the presence of free hydrocyanic acid is suspected, to dis- 
til at first without acidulating; in such cases the stomach should never 
be opened until immediately before the analysis. 



Cyanic Acid. 

Cya?iogen hydrate, tt yO — does not exist in nature; it is obtained 

by calcining the cyanides in presence of an oxidizing agent; or by the 
action of dicyanogen upon solutions of the alkalies or alkaline carbo- 
nates; the best method of obtaining it is by the distillation of cyanuric 
acid. 

It is a colorless liquid; has a strong odor, resembling that of formic 
acid; its vapor is irritating to the eyes, and it produces vesication when 
applied to the skin; it is soluble in water. When free it is readily 
changed by exposure to air into cyamelide. The acid itself is of little 
interest; some of its salts and ethers, however, are of industrial im- 
portance. 

Sulphoeyanic Acid. 

Cyanogen sulphydrate, tt /S — bears the same relation to cyanic 

acid that carbon disulphide does to carbon dioxide. It is obtained by 
the decomposition of its salts, which are obtained by boiling a solution of 
the cyanide with sulphur, by the action of dicyanogen upon the metallic 
sulphide, and in several other ways. 

The free acid is a colorless liquid; crystallizes at — 12.5°; boils at 
102.5°; acid in reaction; sp. gr. 1.04:0 at 17°. The prominent reaction 
of the acid and of its salts is the production of a deep red color with the 
ferric salts; the color being discharged by solution of mercuric chloride, 
but not by hydrochloric acid. 

Sulphoeyanic acid exists in human saliva in combination, probably, 
with sodium. The free acid is actively poisonous and its salts were for- 
merly supposed to be so also; it is probable, however, that much of the 
deleterious action of the potassium salt — that usually experimented with — 
is due as much to the metal as to the acid. 



Metallocyanides. 

The radical cyanogen, besides combining with metallic elements to 
form true cyanides, in which the radical (CN) enters as a univalent atom, 
is capable of combining with certain metals; notably those of the iron 
and platinum groups, to form still more complex radicals, which, combin- 
ing with hvdroafen, form acids, and with basic elements form salts in 
which the analytical reactions of the metallic element entering into the 
radical, are completely masked. Of these metallocyanides the best known 
are those in which iron enters into the radical. As iron is capable of 
forming two series of compounds, in one of which the single atom Fe" 
enters in its divalent capacity, and in the other of which the hexavalent 



342 GENERAL MEDICAL CHEMISTRY. 

double atom (Fe 2 ) vl is contained; so, uniting with cyanogen, iron forms 
two ferrocyanogen radicals: [(CN)' 6 Fe"] iv , ferrocyanogen, and [(CN)' 13 
(Fe 2 ) vl ] vi , ferricyanogen, each of which unites with hydrogen to form an 
acid, corresponding to which are numerous salts: (C 6 N 6 Fe)H 4 , hydrofer- 
rocyanic acid, tetrabasic; and (C 12 N 12 Fe 2 )H 6 , hydroferricyanic acid, hex- 
abasic (see potassium and iron salts). 



COMPOUNDS OF UNKNOWN CONSTITUTION. 

Glucosides. 

Under this head are classed a number of substances, some of them im- 
portant medicinal agents, which are the products of vegetable or animal 
nature; their characteristic property is that, under the influence of a 
dilute mineral acid, they yield glucose, phloroglucine or mannite, together 
with some other substance. Under the supposition that glucose and its 
congeners are alcohols, it is quite probable that the glucosides are their 
corresponding ethers. 

Some of the more important glucosides are treated of below in alpha- 
betical order: 

Amygdalin, C 20 H 27 NO X1 , exists in cherry-laurel and in bitter almonds, 
but not in sweet almonds. Its characteristic reaction is that, in the pres- 
ence of emidsin, which exists in sweet as well as in bitter almonds, 
and of water, it is decomposed into glucose, benzoic aldehyde, and hydro- 
cyanic acid. 

The same reaction is brought about by boiling with dilute sulphuric 
or hydrochloric acids. Bitter almonds contain about two per cent, of 
amygdalin. 

Apiin, C 24 H 28 13 , is a glucoside obtained from parsley. Dilute acids 
decompose it into a white, flocculent substance of unknown composition, 
and a non-fermentable, uncrystallizable sugar. 

Arbutin, C 12 H 16 7 (?) — a glucoside supposed to be the active princi- 
ple of uva ursi, is a bitter, crystalline substance, very soluble in water, 
decomposed by emulsin or by dilute acids into glucose and hydroquinon. 

Carminic acid, C 17 H 18 O 10 , is the red coloring matter of cochenil; 
dilute sulphuric acid decomposes it into a non-fermentable sugar and a 
new red pigment, insoluble in ether, but soluble in alcohol. 

Cathartic acid — a bitter, uncrystallizable glucoside, obtained from 
senna. 

Chitin is an animal product, and forms the organic basis of the 
tissues of insects, spiders, and crustaceans. It withstands the action of 
reagents well, but, when boiled with dilute sulphuric acid, yields ammo- 
nia, a fermentable sug-ar, and a substance which appears to be lactamide. 

Colocynthin — a very bitter and actively purgative glucoside, ob- 
tained from colocynth, soluble in water and alcohol; decomposed by dilute 
acids into a resin, colocynthein, and glucose. 

Crocin — a yellowish red glucoside obtained from saffron; soluble in 
alcohol; decomposed into crocetin and a sugar resembling, but not identi- 
cal with, glucose. 

Digitalin. — The substance known until recently as digitalin was an 
uncrystallizable material, soluble in water, obtained from digitalis, whose 
medicinal properties it possessed to a high degree. More recent re- 
searches have, however, shown that this substance, although very active, 



GLUCOSIDES. 343 

does not contain all the active principles of the plant, which contains the 
true glucoside as a crystalline substance, insoluble in water, but soluble in 
alcohol. By a complicated system of extraction by water and by alcohol, 
and decolorization and purification of the extracts, Nativelle has obtained 
from all parts of the plant, except the seeds, 1st, a gummy, uncrystallizable, 
white substance, soluble in water, sparingly soluble in alcohol; very bitter, 
acrid, and irritating, which he calls amorphous digitaleine / 2d, the true 
glucoside, insoluble digitalin, which crystallizes in fine needles, almost in- 
soluble in water, readily soluble in alcohol; intensely and persistently 
bitter, and actively poisonous. Sulphuric acid dissolves it with a green- 
ish brown color, changing to red under the influence of bromine vapor, 
and to emerald green on subsequent dilution with water. Hydrochloric 
acid of 20° strength dissolves it, the solution assuming in a few moments 
a fine green color. When suspended in water and treated with sulphuric 
acid it is entirely decomposed, with production of glucose and a peculiar 
substance, digitaliretin, C 15 H 2 .0 5 . Digitalis also contains a white, insipid 
crystalline substance, insoluble in water — digitalose, and a crystallizable 
acid — digitalic acid, very soluble in water and in alcohol; very prone to 
decomposition when exposed to light; acid in taste and in reaction. 

For the detection of digitalin in cases of poisoning, see p. 348. 

Glycyrrhizin — a non-crystallizable, 3-ellowish, pulverulent principle, 
obtained from liquorice; soluble with difficulty in cold water, soluble in 
hot water, alcohol, and ether; bitter-sweet in taste. By long boiling with 
dilute acids it is decomposed into glucose and glycyrrhetin, C 18 II 26 4 . 

Jalapin, C 34 H 56 16 , is the active principle of scammony, and exists 
also to a limited extent in jalap (see below). It is an insipid, colorless, 
amorphous substance, which is decomposed by dilute acids into glucose 
and jalapinol. The active ingredient of jalap is not, as the name would 
imply, jalapine, but a resinous substance called convolvulin, which is in- 
soluble in ether, odorless, and insipid. It is not attacked by dilute sul- 
phuric acid, although the concentrated acid dissolves it with a carmine- 
red color, slowly turning to brown; in alcoholic solution it is decomposed 
by gaseous hydrochloric acid into glucose and convolvidinic acid. It is 
an active purgative agent. 

Phlorizin, C 21 H 24 O 10 , is a glucoside obtained from the bark of apple-, 
plum-, pear-trees, etc.; it crystallizes is silky needles; sparingly solub e in 
cold water, very soluble in hot water and in alcohol. Is colored yellow, then 
brown, by sulphuric acid; dilute acids decompose it into glucose and 
phloretin, C 16 _H 14 6 . 

Quercitriiij or quercitric acid — obtained from black-oak bark; crys- 
tallizes in rectangular or rhombic plates; neutral; odorless; bitter; almost 
insoluble in cold water; soluble in hot water and in alcohol; readily soluble 
in alkaline solutions, with a greenish yellow color, turning to brown by 
oxidation on exposure to air. Dilute mineral acids decompose it into iso- 
dulcite, C G H 14 6 , and quercetin, C 27 H 18 12 . 

Quinovin, or quinovatic acid, a bitter principle, possessed of acid 
functions, obtained from the false bark known as cinchona nova/ it is a 
glucoside, being decomposed by dilute acids into a sugar resembling 
mannitan and qidnovic acid. 

Saliein, C 13 H 18 7 — one of the best known of the glucosides; derives 
its name from its chief source, the bark of the willow (saline). It is a 
white, crystalline substance; insoluble in ether, soluble in water and in 
alcohol; fuses at 120°, and is decomposed at a temperature above 200°; it 
is very bitter; its solutions are dextrogyrous, [a] D — 55.8°. Dilute acids 



344 GENERAL MEDICAL CHEMISTRY. 

decompose it into glucose and saligenin (q. v.). Concentrated sulphuric 
acid colors it red, the color being- discharged on the addition of water. 
When taken into the economy it is converted into salicylic aldehyde and 
acid, which are eliminated in the urine. 

Santonin — Santonic acid — C 15 H 18 3 — Bantoninum (U. S., Br.) — a 
glucoside having distinct acid properties; obtained from various species 
of Artemisia (Levant worm-seed). It crystallizes in colorless, rectangular 
prisms, which turn yellow on exposure to light; odorless and tasteless; in- 
soluble in cold water, sparingly soluble in hot water, alcohol, and ether; 
its solutions are faintly acid in reaction. Sulphuric acid, aided by heat, 
decomposes it into glucose and a yellowish, odorless, tasteless resinoid, in- 
soluble in water, soluble in alcohol, called santoniretin. Santonin, in so- 
lution, gives a chamois-colored precipitate with the ferric salts, and a 
white precipitate with silver, zinc, and mercurous salts; no precipitate 
with mercuric salts. 

Patients taking santonin pass urine having the appearance of that 
containing bile, which, when treated with potash, turns cherry-red or 
crimson, the color being discharged by an acid, and regenerated on neu- 
tralization. 

Solanin — a glucoside, having basic properties, existing in different 
plants of the genus Solanum. It crystallizes in fine, white, silky needles; 
having an acrid, bitter taste; insoluble in water, and but sparingly soluble 
in ether and in alcohol. By the action of hot dilute acids it is decom- 
posed into glucose and a basic substance, solanidine; when not heated, 
solanin combines with acids to form uncrystallizable salts. Cold, con- 
centrated sulphuric acid colors it orange-yellow, and finally forms with it 
a brown solution ; nitric acid dissolves it, the solution being at first color- 
less, afterward rose-pink. 

Tannin — Tannic acid — C 14 H 10 O 9 . — Quite a number of different sub- 
stances of vegetable origin, principally derived from barks, leaves, and 
seeds. They are amorphous, soluble in water, astringent, capable of 
precipitating albumen and of forming imputrescible compounds with the 
gelatinoids. They are, with one possible exception, glucosides. The 
principal varieties are the following: 

Gallo-tannic acid — Acidum tannicum (U. S., Br.) — is the best known 
of the tannins, and is obtained from nut-galls, galla (U. S., Br.), which 
are excrescences produced upon oak-trees by the puncture of minute in- 
sects. It appears as a yellowish, amorphous, odorless, friable mass; has 
an astringent taste; very soluble in water, less so in alcohol, almost insol- 
uble in ether; its solutions are acid in reaction, and on contact with ani- 
mal tissues give up the dissolved tannin, which becomes fixed by the 
tissue to form a tough, insoluble, and non-putrescible material (leather). 

Solutions of gallo-tannic acid yield insoluble precipitates with sulphuric, 
hydrochloric, phosphoric, and arsenic acids, sodium chloride, potassium 
acetate, gelatin, and ammonium chloride. It also precipitates solutions 
of most of the metallic salts, in many instances effecting a reduction and 
separation of the metallic element. The tannates of the alkaline metals 
are soluble, and become colored on exposure to air; almost all other tan- 
nates are insoluble, including those of the vegetable alkaloids. 

A freshly prepared solution of pure gallo-tannic acid gives a dark blue 
precipitate with ferric salts, but not with ferrous salts. If, however, the 
solution have been exposed to the air, it is altered by .oxidation, and gives, 
with ferrous salts, a black color, in whose production gallic acid probably 
plays an important part, which is the coloring material of ordinary writing- 



GLUCOSIDES. 345 

ink. A good ink is made by boiling 1 six parts of crushed nut-galls in 
forty-five parts (by weight) of water for three hours, replacing the water 
as it evaporates, cooling and filtering; a solution containing 2.5 parts of 
gurn arabic dissolved in a small quantity of water and strained, and, finally, 
a concentrated solution of 2.5 parts of ferrous sulphate, are added; the 
mixture is exposed to the air until it has assumed the proper tint (two to 
three weeks), decanted, and bottled. The color of this ink is discharged 
by oxalic and sulphuric acids. Removals of writing in iron ink by acids 
may be detected by first moistening with pure water, and testing by lit- 
mus paper; the reaction will be acid, unless the acid have been neutralized; 
the surface is then pencilled with a dilute solution of ammonia, and after- 
ward with a solution of nut-galls, when the writing will become more or 
less plainly visible. 

Other characters of gallo-tannic acid are the formation of precipitates 
with solutions of albuminoids, gelatin, alkaloids, and tartar emetic. Its 
watery solution remains unaltered when protected from air, but by expo- 
sure it becomes colored and mouldy, ferments, and is converted into gallic 
acid; the same changes are caused by dilute acids and in the economy 
when gallo-tannic acid is ingested. 

Although formerly considered as a glucoside, and, in all probability, 
existing as such in vegetable nature, recent researches have shown gallo- 
tannic acid to be, not a glucoside, but digallic acid. 

Caffetannic acid exists in saline combination in coffee and in Paraguay 
tea. It colors the ferric salts green, and does not affect the ferrous salts, 
except in the presence of ammonia; it precipitates the salts of quinine 
and of cinchonine, but does not precipitate tartar emetic or gelatin. It 
is a glucoside, being decomposed by suitable means into caffeic acid and 
mannitan. 

Cachoutannic acid, obtained from catechu, is soluble in water, alco- 
hol, and ether. Its solutions precipitate gelatin, but not tartar emetic; 
they color the ferric salts grayish green. 

Morintanuic acid — Maclurin — a yellow, crystalline substance, ob- 
tained from fustic; more soluble in alcohol than in water. Its solutions 
precipitate green with ferroso-ferric solutions; yellow with lead acetate; 
brown with tartar emetic; yellowish brown with cupric sulphate. It is 
decomposable into phloroglucin and protocatechnic acid. 

Quercitannic acid is the active tanning principle of oak-bark; it dif- 
fers from gallo-tannic acid in not being capable of conversion into gallic 
acid, and in not furnishing pyrogallol on dry distillation. It forms a vio- 
let-black precipitate with ferric salts. The tannin existing in black tea 
seems to be quercitannic acid. 

Quinotannic acid, a tannin existing in cinchona barks, probably in 
combination with the alkaloids. It is a light yellow substance; soluble 
in water, alcohol, and ether; its taste is astringent, but not bitter. Di- 
lute sulphuric acid decomposes it, at a boiling temperature, into glucose 
and a red substance — quinova red. 

The tannin existing in wines, especially in new red wines, appears to 
be a mixture of at least two tannins, one derived from the seeds and 
stems of the grape (none exists in the juice), and the other from the 
wood of the cask; it has the valuable property of forming an insoluble 
compound with albumen, and thus removes and prevents further change 
of the albuminoids. 



346 GENERAL MEDICAL CHEMISTRY. 



NATURAL ALKALOIDS. 

Under this head are classed a number of substances of great interest 
to the physician. They exist for the most part in vegetable nature, com- 
bined with acids, for which reason they are sometimes called vegetable 
bases, or vegetable alkalies/ the comparatively recent discovery, however, 
of substances possessing all the characteristics of alkaloids in materials of 
animal origin, renders these terms inapplicable. 

The alkaloids, as the name implies, bear some resemblance to the al- 
kalies; they are alkaline in reaction, and combine with acids to form salts 
in the same way as does ammonia; there is good reason for believing, 
also, that these salts, as those of the amines (q. v.), are compounds of radi- 
cals bearing the same relation to the alkaloid itself that ammonium bears 
to ammonia: 

2NH 3 + S0 4 H 2 = S0 4 (NH 4 ) 2 



Ammonia. Sulphuric 
acid. 


Ammonium 
sulphate. 


2C 17 H 19 N0 3 + S0 4 H 2 = 


SO, (0, A.3S[0,), 


Morphia. Sulphuric acid. 


Morphonium sulphate. 



They may be divided into two principal groups; those of the first are 
liquid and volatile, and are composed of carbon, hydrogen, and nitrogen; 
the synthesis of one of their number, effected by Schiff, leaves no doubt 
that they are true amines. The members of the second group are solid, 
volatilizable with difficulty, if at all, and are composed of carbon, hydro- 
gen, nitrogen, and oxygen. Although, in spite of much patient research, 
no chemist has hitherto succeeded in effecting the synthesis of an oxygen- 
ated alkaloid, their compounds and the products of their decomposition 
lead us to believe it highly probable that they will be found to be amides. 
The solid alkaloids are all colorless, bitter, insoluble, or sparingly soluble 
in water, and most of them crystallize readily and perfectly. 

A knowledge of certain physical and chemical properties possessed in 
varying degrees by the alkaloids in common, is of great value in phar- 
maceutical and toxicological chemistry. 

/Solubility. — As a rule the alkaloids are insoluble in water, or nearly 
so, more soluble in alcohol, chloroform, petroleum ether, and benzene; 
the solubility of the salts of the alkaloids differs in a remarkable way from 
that of the alkaloids themselves, for, while both are soluble in alcohol, the 
salts are, for the most part, soluble in water and the alkaloids are not; on 
the other hand, the alkaloids are soluble in petroleum ether, benzene, 
ether, chloroform, and amyl alcohol, in which menstrua their salts are 
either insoluble or very sparingly soluble. It is upon these differences of 
solubility that the methods for separating alkaloids, etc., from animal 
tissues are based (see below). 

Rotary power. — All the natural alkaloids exert a rotary action upon 
polarized light, and all, with the exception of cinchonine and quinidine, 
are kevogyrous. As a rule, their rotary action is diminished by combina- 
tion with an acid, in the absence of an excess of acid; with quinine, how- 
ever, the reverse is the case; narcotine, when free, is laevogyrous, but in its 
salts is dextrogyrous. 






NATTJKAL ALKALOIDS. 



347 



The rotary powers of the principal alkaloids are the following: 



Quinine f a] = — 1 26. 7 

Quinidine [a] 

Cinchonine [a] 

Cinchonidine [a] 

Morphine [a] 

Narcotine [a] 



+ 250.75° 
+ 190.4° 
—144.61° 
- 88.04° 
-103.5° 



Codeine [a] = —118.2° 

Narceine [a] — 6.7° 

Strychnine [a] - 132. 07 c 

Brucine [a] - 61.27 c 

Nicotine [a\ — 93.5° 



General reactions. — Potash, soda, ammonia, lime, baryta, and mag- 
nesia precipitate the alkaloids from solutions of their salts. 

Quite a number of reagents have been suggested by various authors, 
which give with solutions of the salts of all the alkaloids, even when very 
dilute, characteristic precipitates. The principal of these reagents are: 

Phosphomolybdic acid. — The reagent is prepared as follows: am- 
monium molybdate is dissolved in water; the solution filtered, and a 
quantity of crystallized hydrodisodic phosphate, one-fifth in weight of the 
molybdate used, is added, and then nitric acid to strong acid reaction; 
the mixture is warmed and set aside for a day or more. The yellow pre- 
cipitate is collected on a filter, washed with water, acidulated with nitric 
acid, and, while still moist, transferred to a porcelain capsule, to which 
the liquid obtained by exhausting the remainder on the filter with am- 
monium hydrate is added. The fluid so obtained is warmed and gradu- 
ally treated with pulverized sodium carbonate until a colorless solution is 
obtained; this is evaporated to dryness, a few crystals of sodium nitrate 
are added to the residue, and the whole gradually heated to quiet fusion, 
and until the ammonia has been expelled. After cooling, the residue is 
dissolved in warm water in the proportion of one to ten, acidulated with 
nitric aoid, and decanted. 

To use the reagent, a drop of the suspected solution is placed upon a 
glass plate with a black background, and near it a drop of the reagent; 
the two drops are then made to mix slowly by a pointed glass rod. In 
the presence of even a minute trace of an alkaloid (or of certain other 
substances) a precipitate is formed, which is bright yellow and flocculent 
with aniline, morphine, veratrine, aconitine, emetine, atropine, hyoscya- 
mine; bright yellow and voluminous with theine, theobromine, conii'ne, 
nicotine; brownish yellow with narcotine, codeine, piperine; yellowish 
white with quinine, cinchonine, strychnine; yolk-yellow with brucine. 

The value of this reagent is not in its capacity to differentiate between 
the various alkaloids, but in its indication of the probable presence or cer- 
tain absence of some alkaloid in appreciable quantity. 

Potassium iodhydrar gyrate, obtained by dissolving 13.546 grams of 
mercuric chloride and 49.8 grams of potassium iodide in a litre of water. 
A very sensitive reagent when applied to alkaloidal solutions which are 
either acid, neutral, or very faintly alkaline in reaction. 

The solution, made of the above strength, may be used for quantitative 
determinations. The reagent is added from a burette to the solution of 
alkaloid until a drop, filtered from the solution which is being tested, and 
placed upon a black surface, gives no precipitate with a drop of the re- 
agent. Each c.c. of reagent used indicates the presence in the volume 
of liquid tested of the following quantities of alkaloids, in grams: 



Aconitine 0.0267 

Atropine . 0145 

Narcotine 0.0213 

Strychnine 0. 0167 



Brucine 0.0233 

Veratrine 0.0269 

Morphine 0.0200 

Comine 0.00416 



Nicotine 0.00405 

Quinine 0.0108 

Cinchonine 0.0102 

Quinidine 0.0120 



348 GENERAL MEDICAL CHEMISTRY. 

Of course, the process can be used only in a solution containing a single 
alkaloid. 

Separation of alkaloids from organic mixtures and from each other. — 
One of the most difficult of the toxicologist's tasks is the separation from 
a mixture of organic material (contents of stomach, viscera) of an alkaloid 
in such a state of purity as to render its identification perfect. The diffi- 
culty is the greater if the amount present be small, as is usually the case; 
and if the search be not confined to a single alkaloid, as frequently occurs. 
Some of these substances, as strychnine, are detectable with much greater 
facility and certainty than others. 

Of the processes hitherto suggested, the best is that of Dragendorff 
(Gerichtl. Chem. Ermittel. der Gifte, p. 141, 1876), it having been 
devised for the detection of any alkaloid or poisonous organic principle 
present in the substances examined, is very exhaustive, and well adapted 
to cases frequently arising in chemico-legal practice; but, on the other 
hand, is too intricate to be serviceable to the general practitioner. 

An abridgment of this process may be of use to detect the presence 
of the more commonly used alkaloids in a mixture of organic material. 
The physician should, however, bear in mind that, in cases liable to give 
rise to legal proceedings, these may become seriously complicated by the 
analysis of any parts of the body, dejecta, or suspected articles of food, 
etc., by any process open to attack by the most searching cross-ex- 
amination. 

The substances to be examined are reduced to a fine state of sub- 
division, and are digested for an hour or more in water acidulated with 
sulphuric acid, at a temperature of 40° to 50°; this is repeated three 
times, the liquid being filtered and the solid material expressed. The 
united extracts are evaporated at the temperature of the water-bath to a 
thin syrup; this is mixed with three or four volumes of alcohol, the mix- 
ture kept at about 35° for twenty-four hours, cooled well and filtered; 
the residue being washed with seventy per cent, alcohol. The alcohol is 
distilled from the filtrate, and the watery residue diluted with water and 
filtered. 

The filtrate so obtained contains the sulphates of the" alkaloids, and 
from it the alkaloids themselves are separated by the following steps: 

First. — The acid watery liquid is shaken with freshly rectified petro- 
leum ether (which should boil at about 65° — 70°, and should be used with 
caution, as it is very inflammable); after several agitations the ether layer 
is allowed to separate and is removed; this treatment is repeated so long 
as the ether dissolves anything. The residue obtained by the evaporation 
of the ether — Residue I.— is mostly composed of coloring matters, etc., 
which it is desirable to remove. 

Second. — The same treatment of the watery liquid is repeated with 
benzene, which on evaporation yields Hesidue II., which is, if crystalline, 
to be tested for cantharidin, santonin, and digitalin (q. v.)' } if amorphous, 
for elaterin and colchicin. 

Third. — The acid, aqueous fluid is then treated in the same way with 
chloroform, to obtain Hesidue III., which is examined for cinchonine, 
digitalin, and picrotoxin by the proper tests. 

Fourth. — The watery fluid, after one more shaking with petroleum 
ether and removal of the ethereal layer, is rendered alkaline with ammo- 
nium hydrate and shaken with petroleum ether at 40°, the ethereal layer 
being removed as quickly as possible while still warm; this is repeated 
two or three times, and repeated with cold petroleum ether, which is re- 



VOLATILE ALKALOIDS. 349 

moved after a time. The warm ethereal layers yield Residue TVa; the 
cold ones Residue TVb. The former is tested for strychnine, quinine, 
brucine, veratrine; the latter for coniine and nicotine. 

Fifth. — The alkaline, watery fluid is shaken with benzene, which, on 
evaporation, yields Residue V., which may contain strychnine, brucine, 
quinine, cinchonine, atropine, hyoscyamine, physostigmine, aconitine, co- 
deine, thebaine, and narceine. 

Sixth. — A similar treatment with chloroform yields Residue VI., which 
may contain a trace of morphine. 

Seventh. — The alkaline liquid is then shaken with amyl alcohol, which 
is separated and evaporated; Residue VII. is tested for morphine, solanin 
and salicin. 

Eighth. — Finally, the watery liquid is itself evaporated with pounded 
glass, the residue extracted with chloroform, and Residue VIII., left by 
the evaporation of the chloroform, tested for curarine. 



Volatile Alkaloids. 

Coniine — Conicine — Cicutine — C 8 H t5 N — was discovered in 1827, and 
is obtained from Conium maculatum, in which it is accompanied by two 
other alkaloids, methyl-coniine, C 8 H 14 N (CH 3 ), and conhydrin, C 9 H 17 NO 
— the former a volatile liquid, the second a crystalline solid. 

Coniine is a colorless, oily liquid; has an acid taste and a disagreeable 
penetrating odor; sp. gr. 0.878; can be distilled when protected from 
air; boils at 212°; exposed to air it resinifies; it is very sparingly solu- 
ble in water, but is more soluble in cold than in hot water; soluble in all 
proportions in alcohol, soluble in six volumes of ether, very soluble in 
fixed and volatile oils. 

The vapor which it gives off at ordinary temperatures forms a white 
cloud when it comes in contact with a glass rod moistened with hydro- 
chloric acid, as does ammonia. It forms salts which crystallize with 
difficulty. Chlorine and bromine combine with it to form crystallizable 
compounds; iodine in alcoholic solution forms a brown precipitate in al- 
coholic solutions of coniine, which is soluble without color in an excess. 
Oxidizing agents attack coniine with production of butyric acid (see 
below). The iodides of ethyl and methyl combine with coniine to form 
iodides of ethyl and methyl-conium. It has been obtained synthetically 
by first allowing butyric aldehyde and an alcoholic solution of ammonia 
to remain some months in contact at 30°, when dibutyraldine is formed. 

2(C 4 H 8 0) + NH 3 = C 8 H n NO + H 2 

Butyric Ammonia. Dibutyraldine. Water, 

aldehyde. 

The dibutyraldine thus obtained is then heated under pressure to 150° — 
180°, when it loses water: 

C,H„NO = C 8 H 16 N + H,0 

Dibutyraldine. Coniine. Water. 



350 GENERAL MEDICAL CHEMISTRY. 

A synthesis which, in connection with the decompositions of coni'ine, 

(0,H,)' ) 
shows its rational formula to be (C 4 H 7 )' > N. 

H . ) 

The characteristic reactions of coniine are: 1st, treated with dry hy- 
drochloric acid gas it turns reddish purple and then deep indigo-blue; 
the aqueous acid of sp. gr. 1.12, when evaporated from coni'ine leaves a 
greenish blue, crystalline mass; 2d, iodic acid forms a white precipitate 
in alcoholic solutions of coni'ine; 3d, with sulphuric acid it forms a sul- 
phate which by evaporation of the acid turns red and then green, giving 
off an odor of butyric acid. 

When taken internally it is an active poison, causing death by as- 
phyxia, often as quickly as prussic acid. 

Nicotine, C 10 H 14 N 2 — exists in tobacco in different proportion in dif- 
ferent varieties, from two per cent, to eight per cent. 

It is a colorless, oily liquid, which turns brown on exposure to light 
and air; has a burning, caustic taste and a disagreeable, penetrating 
odor; it distils at 250°; it burns with a luminous flame; sp. gr. 1.027 at 
15°; it is very soluble in water, alcohol, the fatty oils, and ether; the 
last-named fluid removes it from its aqueous solution when the two are 
shaken together; it absorbs water rapidly from moist air. Its salts are 
deliquescent and crystallize with difficulty. 

Its principal reactions are: 1st, an ethereal solution of iodine added 
to an ethereal solution of nicotine separates at first a reddish brown, res- 
inoid oil, which gradually becomes crystalline, and there separate from 
the solution crystalline needles, often one to two inches long, which are 
ruby red by transmitted, and dark blue by reflected light; 2d, it turns 
violet when heated with hydrochloric acid; 3d, it is colored orange-yellow 
by nitric acid. 

Nicotine is an active poison, being fatal to dogs in doses of 2 — 3 
drops, by causing asphyxia. It is interesting in the history of toxi- 
cology as having been used in a case of criminal poisoning, for the inves- 
tigation of which Stas devised the first systematic method of searching 
for the alkaloids. 

Fixed Alkaloids. 

These are much more numerous than those which are volatile, and 
form the active principles of a great number of poisonous plants. As we 
are yet in the dark as to the constitution of these bodies, the only classi- 
fication which we can adopt is the temporary one based upon the botanic 
characters of the plants from which they are derived. 



Opium Alkaloids. 

Opium is the inspissated juice of the capsules of the poppy. It is of 
exceedingly complex composition, and contains, besides a neutral body 
called meconine, probably a polyatomic alcohol, C 10 H 10 O 4 , a peculiar acid, 
meconic acid (q. v.), lactic acid, gum, albumen, wax, and a volatile mat- 
ter — no less than eighteen different alkaloids, one or two of which, how- 
ever, are probably formed during the processes of extraction, and do not 
pre-exist in opium. 



OPIUM ALKALOIDS. 



351 



The following is a list of the constituents of opium, those marked * 
being of medical interest: 



Name. 



*Meconic acid. . 

Lactic acid 

Meconine 

* Morphine 

Pseud o m orphin e 
Hy drocotarnine . 

*Codeine 

*Thebaine 

Protopine 

Rhseadine 

Codamine 



Formula. 



C 7 H 4 7 

CoHb03 

CM0H10O4 

!C 17 H 19 N0 3 

C 17 H 19 N0 4 

l2 H l6 NO 8 

C 18 H 21 N0 3 

C 19 H 21 N0 3 

C^oHio^NOs 

C 20 H 21 NO 

C 30 H 36 NO 



Percent, in 
Smyrna 
opium. 


Percent, in 
Constantino- 
ple opium. 


4.70 


4.38 


1.25 


, 


0.08 


0.30 


10.30 


4.50 


0.25 


1.52 


0.15 


.... 









Name. 



Laudanine . . . 
Papaverine. . . 

Opianine 

Meconidine . . 
Cryptopine . . . 
Laudanosine . 
*Narcotine . . 
Lanthopine . . 
*Narceine. . . . 
Porphyroxine 



Formula. 



C 20 H, 5 NO 

C ai H 21 N0 4 

C 21 H 21 NG 7 

C 21 H 23 N0 4 

C 21 H 23 N0 

C 91 H 27 N0 4 

C a2 H 23 N0 7 

C 23 H 2B N0 4 

C a3 H 29 N0 



ji S'3. 

Sao 



1.00 

1.80 

0.71 



o . 

Sh -, e> 

^6 ft 



3.47 
0.42 



Morphine, C 17 H 19 NO,-f-Aq. — TJiis alkaloid was probably obtained in 
an impure form by Boyle in the seventeenth century. In 1803 Seguin, 
Derosne, and Sertuerner almost simultaneously obtained crystalline prin- 
ciples from opium, but failed to recognize their basic character; it was 
only in 1S17 that Sertuerner recognized the true nature of morphine, and 
was thus the first to discover a vegetable alkaloid. 

Morphine crystallizes in colorless prisms; odorless, but very bitter; it 
fuses at 120°, losing its water of crystallization; more strongly heated, ifc 
swells up, becomes carbonized, and finally burns. It is soluble in 1000 
pts. of cold water, in 100 pts. of boiling water; in 20 pts. of alcohol of 
0.82, and in 13 pts. of boiling alcohol of the same strength; in 390 pts. of 
cold amyl alcohol, much more soluble in the same liquid warm; almost 
insoluble in aqueous ether; rather more soluble in alcoholic ether; almost 
insoluble in benzene; soluble in 60 pts. of chloroform. All the solvents 
dissolve morphine more readily and more copiously when it is freshly pre- 
cipitated from solutions of its salts than when it has assumed the crystal- 
line form. 

Morphine combines with acids to form crystallizable salts, of which the 
chloride, sulphate, and acetate are used in medicine. The action of hy- 
drochloric acid upon morphine is interesting; if morphine be heated for 
some hours with excess of hydrochloric acid, under pressure, to 150°, it 
loses water and is converted into a new base — apomorphine, C J7 H 17 N0 2 — 
a valuble emetic, which may be administered hypodermically. It is a crys- 
talline solid, soluble in ether. 

Tests for morphine. — 1st. Nitric acid colors it red, changing to yel- 
low. 2d. If a fragment of morphine be moistened with cold concentrated 
sulphuric acid and allowed to stand twenty-four hours, a colorless solution 
remains, which turns pink or red on the addition of a trace of nitric acid. 
If, as is almost invariably the case, the sulphuric acid contain nitric 
acid, the red color is produced without addition of nitric acid. The fluid, 
when warmed, cooled, and diluted with water, turns deep mahogany brown 
on the addition of a splinter of potassium dichromate. 3d. A mixture of 
morphine and cane-sugar (one to four) added to concentrated sulphuric 
acid, communicates to it a dark red color, which, when dealing with very 
small quantities of morphine, can be brought out by the addition of a drop 



352 GENERAL MEDICAL CHEMISTRY. 

of bromine water. 4th. Morphine reduces solutions of iodic acid with liber- 
ation of iodine. The test is best applied by adding to the morphine resi- 
due, on a watch-glass, a drop or two of chloroform, then a few drops of a 
solution of iodic acid, and stirring; if morphine be present, the chloroform 
is colored violst. This reaction is quite delicate, and, in the absence of 
other reducing agents, characteristic of morphine, as it is not brought 
about by any other vegetable alkaloid. 5th. A neutral solution of a mor- 
phine salt colors neutral solution of ferric chloride a deep blue. 6th. If a 
solution of molybdic acid in sulphuric acid (Frohde's reagent) be added to 
a trace of morphine or of a morphine salt, it is colored a beautiful violet 
by the reduction of the molybdenum compound; the color gradually 
changes to blue, then to a dirty green, and finally to a very faint pink; it 
is instantly discharged on the addition of water. 7th. A solution of ace- 
tate of morphine, warmed with an ammoniacal solution of silver nitrate, 
produces a gray precipitate of metallic silver; the filtrate turns red or pink 
on the addition of nitric acid. 8th. Auric chloride forms, with solutions 
of morphine, a yellow precipitate, which subsequently turns violet-blue. 

Codeine, C ]8 H 21 N0 3 + Aq. — crystallizes in large rhombic prisms, or, 
from ether without water of crystallization, in octahedra; it is bitter; sol- 
uble in 80 pts. of cold water, 17 pts. of boiling water; very soluble in al- 
cohol, ether, chloroform, benzene; almost insoluble in petroleum ether; 
fuses at 158°. 

It dissolves in cold, concentrated sulphuric acid, the solution being 
colorless, but assuming a blue color after several days, or immediately on 
being warmed. Frohde's reagent (see Morphine) dissolves it with a dirty 
green color, which, after a time, turns to blue. Neutral solution of ferric 
chloride is only colored blue by it after the addition of sulphuric acid. It 
combines with iodine to form a ruby-red or violet compound. 

Codeine is probably derived from morphine by the substitution of 
methyl (CH„) for an atom of hydrogen, C 17 H 18 (CH 1 )NO, = C 18 H 91 NO„ be- 
cause, by acting upon codeine with hydrochloric acid, as in the formation 
of apomorphine from morphine, that base is formed along with methyl 
chloride: 

C 18 H 21 N0 3 + HC1 == C 17 H 17 N0 2 + H 2 + CH 3 C1 

Codeine. Hydrochloric acid. Apomorphine. Water. Methyl chloride. 

Narceine, C 3S H O9 N0 9 + 2 Aq. — crystallizes in fine, prismatic needles; 
bitter; sparingly soluble in water, alcohol, and amyl alcohol — much more 
soluble in the same solvents when warm; insoluble in ether, benzene, and 
petroleum ether; it fuses at 92°; at 100° it loses 1 Aq., and the other at 
140°; at which temperature it is decomposed into amorphous products. 

It dissolves in concentrated sulphuric acid with a gray-brown color, 
which, slowly at ordinary temperatures, rapidly when heated, changes to 
blood-red. Frohde's reagent colors it first dark olive-green, which passes 
after a time, or, when heated, to red; if an incipient red color have been 
obtained by heating the mixture, it on cooling gradually turns blue, be- 
ginning at the edges. It is colored blue-vioiet by iodine solution, like 
starch. A solution of iodine in potassium iodide solution causes, in nar- 
ceine solutions, an amorphous brown precipitate, which, after a time, be- 
comes crystalline and lighter in color. 

Narcotine, C 22 H 23 N0 7 — crystallizes readily in transparent prisms; 
fuses at 177°, and, when fused, crystallizes at 130°, and at 220° it is de- 
composed, ammonia is given off, and hemipinic acid, C 20 H JC O 12 , remains; 



CINCHONA ALKALOIDS. 353 

it is almost insoluble in water, readily soluble in alcohol, ether, and ben- 
zene, insoluble in petroleum ether, and in water faintly acidulated with 
acetic acid; chloroform removes it from its hydrochloric acid solution 
when the two are shaken together. 

Its salts are for the most part uncrystallizable, unstable, and readily 
soluble in water and alcohol. Concentrated sulphuric acid dissolves it, 
the solution being at first colorless, but turns yellow in a few moments, 
and finally, after a day or two, red. Its solution in dilute sulphuric acid 
if very gradually evaporated, turns first orange-red, and then, from the 
periphery toward the centre, bluish violet, and finally, when the acid be- 
gins to volatilize, reddish violet. A solution of narcotine in cold con- 
centrated sulphuric acid is colored red by the introduction of a trace of 
nitric acid; if the sulphuric acid contain nitric acid, the red color appears 
on dissolving the alkaloid. Frohde's reagent dissolves it with a greenish 
color, passing to cherry-red. 

Thebaine — Paramorphine — C 19 H 21 N0 3 — probably the most actively 
poisonous of the opium alkaloids, crystallizes in white, silvery plates; 
fuses at 93°; is without taste when pure; insoluble in water, soluble in 
alcohol, ether, and benzene; its salts are readily soluble in water and 
alcohol. 

Concentrated sujphuric acid is immediately colored bright red by it, 
the solution gradually turning yellowish red. Chlorine, bromine, and 
nitric acid attack it energetically. Frohde's reagent behaves with it like 
sulphuric acid. Sulphuric acid containing nitric acid is colored reddish 
orange by it. Its solution in chlorine water is colored dark reddish brown 
by ammonia. 

IVCeconic acid, C 7 H 4 7 + 3Aq. — a tribasic acid existing in opium m 
combination with a part, at least, of the alkaloids. It is obtained from 
the calcic meconate resulting from the preparation of morphine. It crys^ 
tallizes in small prismatic needles; has an acid, astringent taste; loses 
its water of crystallization at 120°; quite soluble in water, soluble in aK 
cohol, sparingly soluble in ether. 

The characteristic reaction of meconic acid is the production of a 
blood-red color with ferric chloride; the color is not discharged by dilute 
acids or by mercuric chloride, but is discharged by stannous chloride and 
by alkaline hypochlorites (see p. 341). 

The reactions of meconic acid and of narcotine are of great value to 
the toxicologist in enabling him to distinguish between poisoning by 
morphine and that by opium or its preparations. 



Cinchona Alkaloids. 

Although by no means so complex as opium, cinchona bark contains 
a great number of substances: quinine, cinchonine, quinidine, cinchoni- 
dine, aricine; quinic, quinotannic, and quinovic acids; cinchona red, etc. 
Of these the most important are quinine and cinchonine. 

Quinine, C 20 H 24 N 2 O 2+n Aq. — discovered in 1820, by Pelletier and 
Caventou. It exists in the bark of a variety of trees of the genera Cin- 
chona and China, indigenous in the mountainous regions of the north of 
South America, which vary considerably in their richness in this alkaloid, 
and consequently in value; the best samples of calisaya bark contain 
from 30 to 32 parts per 1,000 of the sulphate; the poorer grades 4 to 20 
23 



354 GENERAL MEDICAL CHEMISTRY. 

parts per 1, 000; inferior grades of bark contain from mere traces to 6 
parts per 1,000. 

It is known in three different states of hydration, with one, two, and 
three molecules of water, and anhydrous. The anhydrous form is an 
amorphous, resinous substance, obtained by evaporation of solutions in 
anhydrous alcohol or ether. The first hydrate is obtained in crystals by 
exposing to air recently precipitated and well- washed quinine; the second 
by precipitating by ammonia a solution of quinine sulphate, in which hy- 
drogen has been previously liberated by the action of zinc upon sulphuric 
acid; it is a greenish, resinous body, which loses H 2 at 150°. The 
third, that to which the following remarks apply, is formed in the pro- 
cesses of manufacture by precipitating solutions of quinine salts with 
ammonia. 

It crystallizes in hexagonal prisms; is very bitter; fuses at 120°; 
becomes colored, swells up, and, finally, burns with a smoky flame. It 
does not sublime. It dissolves in 2,200 pts. of cold water, in 760 of hot 
water; very soluble in alcohol and chloroform; soluble in amyl alcohol, 
benzene, fatty and essential oils, and ether. Its alcoholic solution is 
powerfully kevogyrous, according to the most recent observations the 
value of [a] D = — 270.7° at 18°, which is diminished by increase of tem- 
perature, but increased by the presence of acids. 

The decompositions of quinine, although of great interest to the 
chemist as affording indications, slight at present, which may lead to its 
artificial production, are of little direct interest in this place. 

Dilute sulphuric acid dissolves quinine, forming colorless, but fluores- 
cent solutions (see below). Quinine, or its salts, in solution, is colored 
green when treated first with chlorine, and then with ammonia. A cur- 
rent of chlorine passed through water holding quinine in suspension, 
forms a red solution. A solution of quinine treated with chlorine water, 
and then with some fragments of potassium ferrocyanide, is colored pink, 
passing to red. 

Quinine is not used in medicine in the free state, but in the form of 
its salts, the most important of which are: 

Sulphate — Disalphate — Quinios sulphas — (U. S., Br.) — S0 4 (C 20 H 24 
N 2 2 ) 2 H- 7 Aq. — is the form usually met with. It crystallizes in pris- 
matic needles; very light; intensely bitter; phosphorescent when heated 
to 100°; fuses readily, loses its water of crystallization at 120°, turns red, 
and finally carbonizes; it eflloresces on contact with air, losing 6 Aq. ; 
soluble in 740 pts. of water at 13°, and in 30 pts. of boiling water; in 60 
pts. of alcohol; almost insoluble in ether. 

Its solution, mixed with an alcoholic solution of iodine, deposits a 
brilliant green crystalline compound. Quinine sulphate, in the presence 
of water, treated with an excess of dilute sulphuric acid, is dissolved, the 
solution containing the 

Hydrosulphate, SO.H (C 20 H Q4 N 2 O 2 ) + 7 Aq. — which is consequently 
the salt present in most medicinal solutions of quinine. It may be crys- 
tallized in long, silky needles, or in short, rectangular prisms. It differs 
from the preceding salt in its much greater solubility in water, being dis- 
solved by 11 pts. of that solvent at 13°. Its solutions exhibit in a 
marked manner the phenomena of fluorescence, being colorless, but show- 
ing a fine, pale blue color when illuminated by a bright light against a 
dark background, or by transmitted light. 

JBisulphate, O 20 H 24 N 2 O 2 (S0 4 H 2 ) 2 + 7 Aq. — a compound obtained by 
evaporating a solution of the preceding salt in the presence of an excess 



CINCHONA ALKALOIDS. , 355 

of moderately concentrated sulphuric acid. It forms white, prismatic 
needles; very soluble in water; is colored reddish brown by exposure to 
light; its solution is highly fluorescent. 

Owing to the high price of the salts of quinine, they are largely adul- 
terated. Pure quinine should respond to the following tests: when a 
gram of it is shaken up in a test-tube with 15 c.c. of ether and 2 c.c. of 
aqua ammonise, the liquids should subsequently separate into two clear 
layers, without any milky zone between them (cinchonine). When dis- 
solved in hot water, precipitated with an alkaline oxalate and filtered, the 
filtrate should not precipitate with ammonia (quinidine). It should be 
completely soluble in water acidulated with sulphuric acid (fats, resins). 
It should dissolve completely in dilute, boiling alcohol (gum, starch, alka- 
line and earthy salts). It should not be blackened by sulphuric acid 
(cane-sugar). It should not be colored red or yellow by sulphuric acid 
(salicin and phlorizin). When burned upon platinum foil, it should leave 
no residue (mineral substances). 

Cinchonine — C 20 H 24 N 2 O — accompanies quinine in Peruvian bark, in 
which it is present in less amount, varying from 2 to 12 pts. per 1,000; 
and in some cases, as in yellow Guayaquil bark, reaching 30 pts. per 1,000. 

It crystallizes in colorless prisms or needles without water of crystal- 
lization; fuses at 150°, and at 220° is partly sublimed in fine needles and 
partly decomposed; it is soluble in 3,810 pts. of water at 10°, in 2,500 
pts. of boiling water; in 140 pts. of alcohol of sp. gr. 0.852 at 10°; in 
371 pts. ether at 20°; in 40 pts. chloroform; dextrogyrous, [a] = -{-190.4°; 
alkaline; bitter. 

Although cinchonine differs from quinine in composition only by one 
atom of oxygen less, all attempts to convert the former into the latter 
alkaloid by oxidation have only resulted in the formation of an isomere 
of quinine — oxy cinchonine. 

The salts of cinchonine resemble those of quinine in composition, but 
differ from them in being much more soluble in water and alcohol, and 
in not being fluorescent; they are permanent in air, and become phos- 
phorescent when heated to 100°. 

Two other alkaloids derived from plants related to the cinchona re- 
quire mention. 

Caffeine — Theine — Guaranin — C 8 H 10 N 4 O 2 -f- Aq. — exists in coffee, 
tea-leaves, Paraguay tea, and other plants. 

It crystallizes in long, silky needles; faintly bitter; soluble in 93 pts. 
of water at 12°, 158 pts. strong alcohol, or 218 pts. ether. Hot, fuming 
nitric acid converts it into a yellow liquid, which turns purple on the addi- 
tion of ammonia; on boiling, the mixture is decolorized and white crystals 
of cholestrophane, a methyl derivative of parabanic acid (q. ?;.), separate. 
Chlorine acting on caffeine in the presence of water, yields a methyl de- 
rivative of alloxantine (q. v.) — amalic acid. 

Emetine — C 30 H 44 N 2 O 8 — a poisonous alkaloid to which ipecacuanha 
owes its activity. It appears as a white, amorphous, somewhat bitter pow- 
der, almost insoluble in cold water; sparingly soluble in hot water, alco- 
hol, chloroform, and ether; soluble in benzene and petroleum ether. 

Concentrated sulphuric acid forms with it a greenish brown solution. 
Sulphuric acid containing nitric acid colors it green, changing to yellow. 
Frohde's reagent dissolves it immediately with a red color, passing soon 
to a yellowish green, then to green. 



356 GENERAL MEDICAL CHEMISTRY. 



Alkaloids of the Loganiacese. 

Strychnine, C 21 II 22 N 2 2 — discovered in 1818 by Pelletier and Caven- 
tou, in the St. Ignatius bean and subsequently in other varieties of 
Strycknos. The sources from which the alkaloid is now almost exclusively 
obtained are the seeds of the StrycJmos nux vomica, and the bark of the 
same tree, known as false Angostura bark / the seeds contain about 0.5 
per cent of strychnine. 

Strychnine crystallizes upon spontaneous evaporation of its solutions 
in orthorhombic prisms; by rapid evaporation or sudden cooling of its 
solutions it separates as a white powder. Its solutions are alkaline in re- 
action and have an intensely bitter taste, which is perceptible in a solu- 
tion containing only 1 part in 600,000. It is very sparingly soluble 
in water (in 6,GC7 parts of cold and in 2,500 parts of warm water). Its 
solubility in alcohol varies with the strength of the solvent; it is insolu- 
ble in absolute alcohol; 1 part of strychnine is soluble in 120 parts of 
alcohol of sp. gr. 0.8G3 at the ordinary temperature, and in 10 parts of the 
same alcohol at the boiling-point; a weaker alcohol, of sp. gr. 0.936 dis- 
solves 1 part in 240 in the cold. It is insoluble in absolute ether, very 
sparingly soluble in commercial ether. Benzene and amyl alcohol dissolve 
1 part to 200-250. Its best solvent is chloroform, which is capable of 
dissolving twenty per cent, of strychnine. It is also sparingly soluble in 
creasote, the fatty and volatile oils, glycerin, and carbon disulphide. 
From most of these solutions it may be obtained in the crystalline form 
by evaporation. The alcoholic solutions are kevogyrous, [a] j = — 132° — 
136°; the acid solutions are much less active. Strychnine cannot be 
fused without undergoing decomposition, and is only partially capable of 
sublimation. 

Strychnine is a powerful base; it neutralizes the strongest acids, being 
dissolved (with formation of a sulphate) without decomposition in con- 
centrated sulphuric acid; it also precipitates many metallic oxides from 
solutions of the corresponding salts. 

The salts of strychnine are for the most part crystallizable, soluble in 
water and in alcohol, and are all intensely bitter. Of the salts of strych- 
nine the neutral sulphate, S0 4 H 2 (C 21 H 22 N 2 2 ) 2 H-7Aq., is generally used 
medicinally in place of the alkaloid; it crystallizes in rectangular prisms, 
soluble in ten parts of water; the water of crystallization is driven off by 
heat or in vacuo. The acetate is exceedingly soluble in water, and only 
crystallizes in the presence of an excess of acid. 

By the action of chlorine upon solutions of strychnine, compounds are 
obtained in which one or three atoms of hydrogen are replaced by atoms 
of chlorine; these chlorine derivatives possess basic properties. By the 
action of iodine upon strychnine, a peculiar substance called iodostrych- 
nine, 4C 21 H 22 N 2 2 ,3I„, is obtained, which crystallizes in alcoholic fluids in 
golden yellow scales. 

The iodides of methyl and of ethyl react energetically with strychnine, 
to form the iodides of methyl or ethylstrychnium, which bear the same 
relation to the alkaloid that the iodide of ammonium bears to ammonia. 
These substances are white, crystalline solids, basic in their nature, which 
in common with similar derivatives of other alkaloids possess the power, 
when injected subcutaneously, of producing effects very similar to those 
of curarine (q. v.). 

By the action of potassium nitrite upon a boiling aqueous solution of 



ALKALOIDS OF THE LOGANIACEJ3. 357 

strychnine sulphate, nitrogen is given off and two oxidized products are 
formed; one, which crystallizes in fine orange-yellow crystals, is oxystrych- 
nine, C 21 H 28 N 2 6 ; the other, forming red crystals, is bioxystrychnine, C 2l 

h»n,o; 

When strychnine is acted upon, with proper precautions, by sulphuric 
acid and potassium chlorate, a crystallizable acid called strychnic acid is 
formed; it seems to be the same substance which, under the name igasuric 
acid, has been obtained from St. Ignatius' beans, and with which the 
alkaloid is probably in combination in nature. 

Tests for strychnine. — 1st. It dissolves without decomposition in con- 
centrated sulphuric acid, the solution being colorless if the alkaloid be 
pure. The alkaloid is precipitated when the solution is diluted and the 
acid is neutralized, preferably with magnesia in very slfght excess. 2d. 
When a fragment of any substance, capable of yielding nascent oxygen 
on contact with concentrated sulphuric acid, is added to a solution of 
strychnine in that acid, the following colors appear: a very transitory 
blue (frequently not perceptible); a brilliant violet, which slowly changes 
to rose-pink, and this in turn to yellow. Of the various oxidizing agents 
which have been recommended, we believe potassium dichromate to be the 
best for the purposes of this test, notwithstanding the opposite opinion 
expressed by Letheby and echoed verbatim by Woodman and Tidy. 

The test is best applied by evaporating, upon a procelain dish or a watch- 
glass (when the latter is used it must be placed upon a white surface 
when the dichromate is added), a drop or two of the solution suspected 
of containing strychnine; the residue is treated with one or two drops 
of concentrated sulphuric acid, which is spread out with a glass rod; a 
small fragment (not powder) of potassium dichromate is then placed upon 
a dry part of the watch-glass and pushed with moderate rapidity from one 
part of the moistened surface to another; if strychnine be present, the 
course of the dichromate will be marked by a violet streak, which passes 
through rose-pink to yellow. 

This reaction is of great delicacy, being capable of showing the pres- 
ence of xo^To g ra i n of strychnine, and if applied to a residue suitably ob- 
tained (see p. 348), is characteristic of the alkaloid. The only known 
substance, in fact, which produces the same play of colors under like con- 
ditions, is eurarine; but, as this substance is quite soluble in water and 
does not pass from its alkaline aqueous solution into the solvents used in 
the process of separation, it cannot find its way into the solutions in 
which strvchnine is sought for, and cannot, therefor, g-ive rise to anv error. 
A somewhat similar reaction is produced by aniline, which may, how- 
ever, be readily distinguished from strychnine by its being liquid or oily, 
while strychnine is solid; by its peculiar odor, strychnine being odorless; 
and by the fact that the reaction only takes place with dilute sulphuric 
acid in the case of aniline, and with the concentrated acid in the case of 
strychnine. The presence of morphine also interferes to a certain extent 
with the action of this test, an interference wmich is, however, of but 
slight practical importance, as morphine is not found in the same residue 
as strychnine (p. 349). In the presence of brucine the reaction takes 
place more slowly, the color only appearing after oxidation of the brucine. 
3d. A dilute solution of potassium dichromate produces in solutions 
of strychnine a yellow crystalline precipitate of strychnine chromate. 
Otto utilizes the formation of this salt for the production of the color re- 
action (2); he advises that the residue containing strychnine be mois- 
tened with dilute solution of potassium dichromate (1 in 200); after a 



358 GENERAL MEDICAL CHEMISTRY. 

few moments the fluid is poured off, the deposit washed, and treated with 
concentrated sulphuric acid, when the characteristic play of colors is ob- 
served. 4th. If a solution of strychnine be evaporated in a depression 
in a strip of platinum foil, the residue moistened with concentrated sul- 
phuric acid, the foil connected with the positive pole of a single cell of 
Grove's or Smee's battery, and a platinum wire from the negative pole 
brought in contact with the surface of the acid, a violet color appears 
upon the surface of the foil (Letheby). 5th. Solutions of strychnine and 
of its salts are intensely bitter, the taste being distinguishable in a solu- 
tion containing one part of the alkaloid in six hundred thousand of water. 
6th. If a solution of strychnine be introduced beneath the skin of the back of 
a frog, the animal exhibits the symptoms of strychnine-poisoning: difficulty 
of respiration; tetanic convulsions induced by the slightest irritation, as by 
striking the table or blowing upon the animal; twitching of the muscles 
during the intervals between the convulsions; dilatation of the pupils 
during the convulsions, and contraction during the intervals; usually em- 
prosthotonos, sometimes opisthotonos. The smallest frogs should be 
selected, and they should be dried with bibulous paper before the injec- 
tion of the solution. This test, which was first suggested by Marshall 
Hall, is very delicate; yrnhj-g- g ra i n °f the acetate (— ^^ 0Q strychnine) in- 
jected into a small frog have produced tetanic spasms in nine and one-half 
minutes, and death in two hours. 7th. When solid strychnine, or a residue 
containing it, is moistened with a solution of iodic acid in sulphuric acid 
a yellow color appears, which soon changes to brick-red, and finally to a 
violet-red (Selmi). 8th. Moderately concentrated nitric acid, in the cold, 
colors strychnine yellow; a pink or red color indicates the presence of 
brucine. 

Strychnine is one of the most stable of the alkaloids, and may remain 
for a long time in contact with putrefying animal matter without under- 
going decomposition. 

Antidotes. — Chloroform, emetics, the stomach-pump, chloral hydrate. 

Brucine, C„H 36 N 9 4 — discovered in 1819 by Pelletier and Caventou, 
is obtained from the alcoholic washings in the preparation of strychnine. 
It forms transparent, oblique, rhomboidal prisms, containing four mole- 
cules of water of crystallization, which are readily given off by exposure 
to dry air. It fuses a little above 100°, and, on cooling, forms an amor- 
phous, waxy mass. Effloresced brucine dissolves in 500 pts. of boiling, 
and in 850 pts. of cold water; the newly crystallized alkaloid is more 
soluble; it is easily soluble in alcohol, chloroform, and amylic alcohol; less 
soluble in benzene, benzine, glycerin, and the volatile oils; insoluble in 
ether and in the fatty oils. It is odorless, intensely and persistently 
bitter. 

Brucine is a powerful base, forming salts which are, for the most part, 
crystallizable and soluble in water. It forms compounds similar to methyl-, 
ethyl-, and iodo-strychnine under like conditions. Its action upon the 
animal economy is similar to that of strychnine, but much less energetic. 

Tests for brucine. — 1st. Concentrated nitric acid gives with brucine a 
bright scarlet color, which soon assumes a yellowish tinge, and finally be- 
comes yellow, especially if heated; upon the addition of stannous chlo- 
ride or of colorless ammonium sulphydrate to the red fluid, it is turned 
to an intense violet. 2d. A solution of brucine assumes a bright red 
color upon the addition of chlorine water or of chlorine gas, the color chang- 
ing to yellowish brown upon the addition of ammonium hydrate. 

The separation of brucine from strychnine is best effected by adding 



ALKALOIDS FROM OTHER SOURCES. 359 

to a solution of the mixed acetates, not too dilute, a solution of potassium 
dichromate ; the strychnine is precipitated as the chromate, while the 
brucine remains in the solution. 

Igasurine — an alkaloid discovered in nux vomica by Desnoix. In 
poisonous activity it is intermediate between strychnine and brucine, which 
alkaloids it resembles in the nature of its action upon the economy. 

Curarine, C 10 H 15 N — an alkaloid obtained from curare or worara, a 
South American arrow-poison. It crystallizes in four-sided, hygroscopic 
prisms; very bitter; faintly alkaline; very soluble in water and in alcohol; 
insoluble in ether and benzene. 

Concentrated sulphuric acid colors it blue; upon the addition of a crys- 
tal of potassium dichromate to this solution, the same changes of color as 
with strychnine (q. v.) are observed, but they take place more slowly. 
Nitric acid colors it purple. 



Alkaloids of the Solanaeeae. 

The alkaloids of this class are solanine, dulcamarine, atropine, bella- 
donine, hyoscyamine, lycine, and duboisine. 

Solanine, 43 H 69 NO 1G — obtained from many species of Solarium. It 
crystallizes in small, white, shining prisms; faintly bitter and nauseous in 
taste; sparingly soluble in water, alcohol, and ether. 

Concentrated sulphuric acid colors it orange-red, passing to violet and 
then to brown. Nitric acid colors it yellow. 

Atropine — Daturine — C 17 H Q3 N0 3 — is the active principle of bella- 
donna. It crystallizes in colorless needles; strongly and persistently bit- 
ter; alkaline; sparingly soluble in water, benzene, and ether; very sol- 
uble in chloroform; it volatilizes when its solutions and those of its salts 
are boiled. If a fragment of potassium dichromate be dissolved in a few 
drops of concentrated sulphuric acid, the mixture warmed, a fragment of 
atropine, and then a drop or two of water added, the mixture being stirred, 
an odor resembling that of orange-blossoms is observed. 

Hyoscyamine, C 15 H 17 NO (?) — the active principle of hyoscyamus 
niger. It forms a yellowish mass, drying with difficulty; has an odor of 
tobacco, and a sharp, disagreeable taste; rather soluble in water, easily 
soluble in alcohol, ether, chloroform, and benzene. 

Duboisine is a newly discovered alkaloid, obtained from a New 
Caledonian plant, whose characters appear to resemble those of atropine. 



Alkaloids from Other Sources. 

Colchicine, C n H 19 N0 5 — from Colchicum auturrmale. Sulphuric acid 
colors it yellow, then green. Nitric acid colors it violet, then green. 
Sulphuric acid, containing nitric acid, colors it violet, turning to orange 
on the addition of an alkali. 

Veratrine, C 32 H B3 N 2 8 — from Veratrum album and V. viride. Cold 
sulphuric acid colors it first yellow, then red, and finally purple. Bromine 
water colors it violet, violet-red. Pure boiling hydrochloric acid colors 
it red. 

Muscarine — from Agaricus muscarius. 

Physostigmine — Eserine — C 15 H 21 N 3 O a — from Physostigma veneno- 
sum, Calabar bean. Sulphuric acid colors it yellow, passing, after a time, 



3 GO GENERAL MEDICAL CHEMISTRY. 

to red, or to reddish brown, on the addition of bromine water. Hypo- 
chlorites color it red at first; the color is discharged by an excess of the 
reagent. 

Cocaine, C 17 H 24 N0 4 — from JErythroxylon coca. 

Aconitine, C 80 H 47 NO, — from Aconitum napellus. "When dissolved in 
aqueous phosphoric acid, and the solution carefully evaporated over a 
small flame, it produces a violet color at a certain point of concentration. 
Dissolved in concentrated sulphuric acid at ordinary temperatures, the 
solution is at first yellow, and passes very slowly through brown and red- 
brown to violet. 

Pilocarpine — the recently discovered alkaloid of jaborandi. It is a 
crystalline base, forming crystallizable salts. 

Ptoamines — Septicine. — Under these names substances of great in- 
terest to the toxicologist have been described in the past few years; they 
are alkaloids obtained from animal tissues in complete or incipient putre- 
faction. They react with the general reagents for the alkaloids; some are 
fixed, others volatile; some are soluble in ether, others insoluble in ether, 
but soluble in amyl acohol; others insoluble in both liquids; some are strong 
reducing agents and respond to the iodic acid test for morphine. They 
give the following color reactions, which may appear or be absent accord- 
ing to the extent to which the putrefaction has progressed, and to the 
method of extraction: with moderately concentrated sulphuric acid a 
violet-red ; the same color with hydrochloric acid containing sulphuric 
acid and warmed; with sulphuric acid and bromine water a more or less 
distinct red, which gradually fades; warmed with nitric acid and afterward 
treated with potassium hydrate, a golden-yellow; with iodic acid, sulphuric 
acid, and sodium bicarbonate, a more or less distinct violet-red. They are 
readily oxidizable, turn brown on contact with air, and give off odors 
resembling those of urine in some instances, of coni'ine in others, and of 
certain flowers in others. They are pungent in taste, and produce a sense 
of numbness in the tongue, and a tickling- sensation in the throat. Of 
those soluble in ether or in amyl alcohol, some are non-poisonous, and 
others actively toxic. 

Although these substances present such striking analogies with the 
vegetable alkaloids, they differ from the more usually employed of the vege- 
table poisons sufncientlv, and in one or more prominent character to such 
an extent, that any fear of their being mistaken for a vegetable poison 
by the toxicologist is groundless. 



ALBUMINOIDS. 

Protein Bodies. 

The substances of this class, exceedingly complex in their chemical 
composition, are the organic substances, par excellence, being never absent 
in living vegetable or animal cells, to whose " life " they are indispens- 
able. 

They are composed of carbon, hydrogen, oxygen, nitrogen, and sul- 
phur; for the most part uncn'stallizable, and prone to putrefaction. They 
are, with some notable exceptions (see Peptones), colloids, and, as such, 
incapable of dialysis. They are all, when dissolved, lsevogyrous, and for 
the most part soluble in water. 

Although the individual members of the group differ from each other 



ALBUMINOIDS. 361 

considerably in their characters, they have many properties in common. 
Thus, they respond to the following General Tests : 1st. Millons' reagent is 
made by dissolving, by the aid of heat, one part of mercury in two parts 
of nitric acid, sp. gr. 1.42; after solution of the mercury, the liquid is di- 
luted with twice its volume of water, and, after standing twenty-four 
hours, decanted from the deposit. This reagent, added to a solution con- 
taining a trace of an albuminoid, colors it purple-red when warmed to 
about 70°. 2d, Xanthoproteic reaction. — Nitric acid colors the albuminoids 
yellow, the color changing to orange on the addition of ammonia. 3d. 
Pettenkofer' s reaction is produced by the albuminoids (see p. 212). 4th. 
If a solid albuminoid be touched with a drop of cupric sulphate solution, 
and then with a drop of caustic potassa solution, and finally washed, a 
violet mark remains. The same effect is produced in solutions (see p. 264). 
5th. A solution of an albuminoid in excess of glacial acetic acid is colored 
violet, and rendered faintly fluorescent, when treated with concentrated 
sulphuric acid. 6th. Solutions of the albuminoids strongly acidified with 
acetic acid give a white precipitate with potassium ferrocyanide. 

Decompositions. — When heated with dilute acids they are decora- 
posed into two substances: one insoluble, amorphous, yellowish, called 
hemiprotein y the other, soluble in water, insoluble in alcohol, faintly 
acid, called hemialbumin. A prolonged boiling with moderately con- 
centrated sulphuric acid decomposes the albuminoids into well-defined 
bodies — leucin, tyrosin; aspartic, and glutamic acids. 

Alkalies dissolve the albuminoids more or less readily, forming soluble 
* compounds (see below); when the solution is boiled, a part of the sulphur 
separates in the form of sulphide and hyposulphite. From the alkaline 
solution a substance is precipitated by acids, which is Mulder's protein, 
identical with albumin. Concentrated alkaline solutions decompose them 
into amido-acids. By fusion with alkalies, alkaline cyanides are also pro- 
duced. The action of caustic baryta upon albuminoids has been pro- 
ductive of most interesting results in the hands of Schiitzenberger. 
When heated with caustic baryta and water to 100°, carbonate, sulphate, 
oxalate and phosphate of barium are deposited, and carbon dioxide and 
ammonia given off in the same proportions as would result if urea were 
similarly treated; upon raising the temperature, and finally heating, under 
pressure, at 200°, a crystalline mass is obtained which contains oxalic and 
acetic acids, a number of amido-acids, aspartic and glutamic acids, and a 
substance resembling: dextrin. 

Heated with water, under pressure, at 100°, they are partly dissolved 
and partly decomposed. When exposed to air and moisture they putrefy, 
with formation of ammonia, ammonium sulphydrate, carbon dioxide, vola- 
tile fatty acids, amido-acids of the fatty series, lactic acid, indol (?), alka- 
loids. 

The products of the action of oxidizing agents upon the albuminoids" 
vary with the agent used. A mixture of sulphuric acid and manganese 
dioxide or potassium dichromate, produces aldehydes and acids of the 
fatty and benzoic series, hydrocyanic acid and cyanides. Nitric acid 
forms xanthoproteic acid (see above), and, afterward, derived acids of the 
benzoic series. Bromine and water heated, under pressure, with albumi- 
noids, yield carbon dioxide, oxalic and aspartic acids, amido-acids, and bro- 
mine derivatives of the fatty and benzoic series. Potassium permanganate 
produces from the albuminoids urea, carbon dioxide, ammonia, and water. 

Constitution. — Although our knowledge of the constitution of these 
complex bodies is still very imperfect, the researches of Schiitzenberger 



362 GENERAL MEDICAL CHEMISTRY. 

and others render it probable that they are complex amides, related to the 
ureids (q. v.), and formed by the combination of glycollamine, leucine, ty- 
rosine, etc., with oxygenated radicals of the acetic and benzoic series. 

Classification. — In the present state of our knowledge, the only classi- 
cation of these substances which can be adopted is a temporary one, 
based more upon the physiological relations of the albuminoids than upon 
their chemical characters. 

I. — Soluble in pure water, coagulated by heat. -—The members of this 
class are the true albumins of the white of egg, serum, and vegetable 
albumin. 

II. — Insoluble hi pure water, soluble in water without alteration in the 
presence of neutral salts, alkalies, and acids, and capable of precipitation 
unchanged from these solutions. 

1. Globidins. — Vitellin, myosin, paraglobulin, fibrinogen. 

2. A.nimal caseins. — Milk casein, serum casein. 

3. Vegetable caseins. — Gluten casein, legumin, conglutin. 

4. First terms of decomposition of the albuminoids by acids, alkalies, 
and soluble ferments. — Albuminates (so-called), acid albumin, syntonin, 
hemiprotein, peptones. 

III. — Insoluble in water and only soluble after decomposition. Can- 
not be separated without alteration from their solutions in acids and 
alkalies. — Glutin-fibrin, gliadin, mucedin. 

IV. — Coagulated by heat. — Coagulated albumin and fibrin. 

V. — Amyloid matter. — Lardacein. 

VI. — Collagene bodies. — Collagen, elastin, ossein and its derivatives, 
chondrigen, chondrin, gelatin, keratin. 

VII. — Mucilaginous bodies. — Mucin, paralbumin, colloidin. 

I. — Egg albumin is the longest known of the albuminoids and ex- 
ists in solution, imprisoned in a network of delicate membranes, in the 
white of egg. It is readily obtained in an impure condition by cutting 
the whites of eggs with scissors, expressing through linen, diluting with 
an equal volume of water, filtering and concentrating the filtrate at a 
temperature below +40°; mineral salts, which adhere to it tenaciously, 
are separated by dialysis. It seems to be a mixture of two different sub- 
stances, one of which coagulates at 63°, and has the rotary power [<2]j = 
— 43°; the other coagulates at 74°, and has the value of [a]j = — 2o . 

Its solutions are not precipitated by a small quantity of hydrochloric 
acid, but an excess of that acid produces a deposit which is difficultly 
soluble in hydrochloric acid, water, and salt solution. Its characteristic 
reaction is that it is coagulated by agitation with ether. 

Serum-albumin exists in blood-serum, chyle, lymph, pericardial 
fluid, the fluids of cysts and of transudations, in milk and, pathologically, 
in the urine. It is best obtained from blood-serum, after removal of 
paraglobulin (q. v.), by a tedious process, and only then in a state of 
doubtful purity. It is less abundant in the blood of some animals than 
paraglobulin, but more abundant in that of man. 

Solutions of serum-albumin are laevogyrous [a]j= — 56°; they are not 
precipitated by carbon dioxide, by acetic or orthophosphoric acid, by 
ether or by magnesium sulphate. They are precipitated by mineral 
acids, tannic acid, metaphosphoric acid, and most metallic salts. When 
heated they become opalescent at 60°, and coagulate in the flocculent 
form at 72°— 75°. 

Detection and determination of albumin in urine. — The detection of 
albumen in the urine can be effected by the test by heat, combined with 



ALBUMINOIDS. 363 

that by nitric acid. The clear filtered urine, if alkaline, is just acidulated 
with acetic acid and then heated to boiling; if albumin be present, a 
cloudiness, or precipitate, or even complete solidification, will ensue, and 
will not disappear, but rather augment, on the addition of concentrated 
nitric acid. Neither test alone affords conclusive evidence of the pres- 
ence of albumin. That by heat, while it coagulates albumin, also precipi- 
tates earthy phosphates if they be present in excess; but these are dis- 
solved on the addition of nitric acid. Nitric acid, although it coagulates 
albumin and dissolves the phosphates, precipitates urates if present in 
excess, but, on the other hand, the urates are more soluble in hot than in 
cold solutions, and, consequently, are not precipitated by heat. 

The acidulation of the alkaline urine, previous to heating, is impera- 
tive, as such urine does not respond to the heat-test if it contain a small 
quantity of albumin, unless it be acidulated; nitric acid should not be 
used for this purpose, nor should more acetic acid be added than just 
suffices to render the reaction acid. 

The only chemical method, hitherto devised, of determining the quan- 
tity of albumin in urine with an approach to accuracy, is gravimetric. 
Twenty to fifty cubic centimetres of the filtered urine, according as the 
qualitative testing shows albumin to be present in large or small quantity, 
and diluted with water if the amount of albumin has been sufficient to 
cause solidification, are slowly heated over the water-bath, and, as the 
boiling temperature is approached, three to four drops of acetic acid are 
added; after the urine has been at 100° for a few moments, it is thrown 
upon a filter. The coagulum is washed with boiling water, then with 
water acidulated with nitric acid, then with alcohol, and finally, with 
ether; these repeated washings not only remove impurities, but cause 
the. coagulum to contract, so that it can be readily detached and trans- 
ferred to a weighed watch-glass; upon this it is dried at 115° and the 
whole weighed. 

The determination of albumen by the polarimeter or by volumetric 
methods does not afford satisfactory results. 

Vegetable albumin exists in solution in all vegetable juices, and 
forms the most valuable constituent of those vegetables which are used as 
food. It is coagulated from its solutions at Gl° — 03°, and by nearly all acids. 

II. — Vitelin exists in the yolk of egg and in the crystalline lens. It 
is soluble in dilute solution of sodium chloride, from which it is precipi- 
tated by excess of water, by heating to 75° — 80°, and by alcohol. It is 
not precipitated by solid sodium chloride. It dissolves in weak alkaline 
solutions without alteration and in very dilute hydrochloric acid (one to 
one thousand), by which it is quickly converted into syntonin. 

Myosin is one of the principal constituents of the muscular fibre in 
rigor mortis. As obtained by Kiihne it is a faintly yellow, opalescent, 
distinctly alkaline liquid, which, when dropped into distilled water, de- 
posits the myosin in globular masses, while the water assumes an acid re- 
action. It is insoluble in water, easily soluble in dilute salt solution, 
from which it is precipitated by the addition of solid sodium chloride, or 
by a heat of 55° — 60°. Very dilute hydrochloric acid dissolves and con- 
verts it into syntonin. 

Paraglobulin. — This substance has been described by various authors 
under the names: plasmine (Denis), serum casein (Panum), sei'um glo- 
buline, Jtbrino-plastic matter (Schmidt), serin (Denis), and has been the 
subject of a vast amount of research. 

It exists in blood-serum, in pericardial fluid, hydrocele fluid, lymph 



364 



GENERAL MEDICAL CHEMISTRY. 



and chyle, from which it is obtained by diluting with ten to fifteen vol- 
umes of ice-cold water, treatment of the solution with a strong- current of 
carbon dioxide, and washing the collected deposit with water as long as a 
portion of the filtrate precipitates with acetic acid and potassium ferro- 
cyanide, or with silver nitrate. As so obtained it is a granular substance, 
which gradually becomes more compact; insoluble in water, sparingly sol- 
uble in water containing carbon dioxide; soluble in dilute alkalies, in 
lime-water, in solutions of neutral alkaline salts, in dilute acids. Its so- 
lution in very dilute alkaline fluids is perfectly neutral and is not coagu- 
lated by heat, except after faint acidulation with acetic or mineral acids; 
it is precipitated by a large volume of alcohol; its solutions are also 
precipitated incompletely by dissolving sodium chloride in them to satura- 
tion, and completely by similar solution of magnesium sulphate; this last 
method of precipitation is used for the separation of paraglobulin from 
serum-albumin (see Fibrin). 

Fibrinogen \ after the separation of paraglobulin from blood-plasma, 
as described above, if the liquid be still further diluted and again treated 
with carbon dioxide, a substance is obtained which, although closely re- 
sembling paraglobulin in many characters, is distinct from it, and, unlike 
paraglobulin, it cannot be obtained from the serum separated from coagu- 
lated blood. 

Parag-lobulin and fibrinogen are both soluble in a solution of sodium 
chloride containing five to eight per cent, of the salt; when the degree 
of concentration of the salt solution is raised to twelve to sixteen per 
cent., the fibrinogen is precipitated, while the paraglobulin remains in so- 
lution and is only precipitated, and then incompletely, when the percent- 
age of salt surpasses twenty (see Fibrin). 

jyiilk casein, the most abundant of the albuminoids of the milk of 
mammalians, closely resembles alkali albuminates, with which it is proba- 
bly identical, as the main point of distinction lias been found to be with- 
out significance; unlike pure alkali albuminates, casein is coagulated 
from its solution by rennet (the product of the fourth stomach of the 
calf) at 40°; but it has been found that alkali albuminate is also so co- 
agulated when milk-sugar and fat are added to the solution. 

Milk. — The secretion of the mammary gland is water holding in solu- 
tion casein, albumin, lactose, and salts, and fat in suspension. Cream 
consists of the greater part of the fat, with a small proportion of the 
other constituents of the milk. Skim milk is milk from which the cream 
has been removed. JButtermilk is cream from which the greater part of 
the fat has been removed, and consequently is of about the same compo- 
sition as skim milk. 

The composition of milk differs in animals of different species: 



Water. . . . 
Solids 
Casein . . . 
Albumin. . 

Fat 

Lactose . . . 
Salts 



Human. 



88.35 
11.65 

3.15 

3.87 
4.37 
0.26 



Cow. 


Goat. 


Sheep. 


Ass. 


Mare. 


Cream. 

i 


84.28 


86.85 


83.30 


89.01 


90.45 


45.99' 


15.72 


13.52 


16.60 


10.99 


9.55 


54.01 


3.57 

0.78 


2.53 
1.26 


i 5.73 


3.57 


2.53 


6.33 


6.47 


4.34 


6.05 


1.85 


1.31 


43.97 


4.34 


3.78 


3.96 


I 5.05 


j 5.43 


3.28 


0.63 


0.65 


0.68 


\ 0.29 


0.42 



Condens- 
ed milk. 



74.32 

16.83 

10.27 
44.33* 

2 80 



* Including 28.98 parts of cane-sugar. 



ALBUMINOIDS. 



365 



The composition of cows' milk varies considerably according to the 
age, condition, breed and food of the cow; to the time and frequency of 
milking; and to whether the sample examined is from the first, middle, or 
last part of each milking. 

Cows' milk is very frequently adulterated, both by the removal of 
the cream and the addition of water. For ordinary purposes, the purity 
of the milk may be determined by observing the specific gravity and the 
percentage of cream by the lactometer and creamometer, neither of which, 
used alone, affords indications which can be relied upon. The specific 
gravity should be observed at the temperature for which the instrument 
is made, as in a complex fluid such as milk no valid correction for tem- 
perature is practical; it ranges in pure milk from 1027 to 1034, it being 
generally the lower in milk which has been watered, and in such as is very 
rich in cream, and the higher the less cream is present. The following 
table, from Hassall, indicates the relations between specific gravity and 
percentage of cream: 



Specific gravity at 15.5° . 
Cream by creamometer.. 
Specific gravity at 15.5° . 
Cream by creamometer . . 



1034.5 


1029.7 


1030.4 


1031.3 


1032,1 


9.0 


7.5 


11.0 


9.0 


11.0 


1031.2 


1028.8 


1030.3 


1032.3 


1029.9 


21.0 


12.0 


15.3 


18.3 


13.2 



1027.5 
20.5 

1030.6 
13.8 



Average specific gravity, 1030.7. Average per cent, of cream, 13.5. 

The percentage of cream is determined by the creamometer: a glass 
tube about a foot long and half an inch in diameter, the upper fifth (ex- 
cluding about an inch from the top) being graduated into hundredths of the 
whole, the being at the top. To use it, it is simply filled to the 
with the milk to be tested, set aside for twenty hours and the point of 
separation between milk and cream read off. It should be above eight 
per cent. 

This method of determining the purity of milk, although sufficient 
for ordinary purposes, should not be considered as affording evidence 
upon which to base legal proceedings; in such cases nothing short of a 
chemical determination of the percentage of fat, and of solids not fat. 
should be accepted as evidence of the impurity of milk. 

Serum-casein is a substance obtained by Kuhne and Eichwald from 
blood-serum diluted with ten volumes of water, freed from paraglobulin 
by carbon dioxide, and from albumin by acetic acid and heat. It is 
insoluble in salt solutions, slowly soluble in a one per cent, solution of 
sodium hydrate. Such a solution is partially precipitated by carbon 
dioxide, almost completely by acetic acid, and completely by heating with 
excess of powdered sodium chloride; incompletely soluble in dilute hydro- 
chloric acid. 

Gluten-casein. — That portion of crude gluten (a soft, elastic, grayish 
material best obtained from flour) which is insoluble in alcohol, hot or 
cold; Legumin, a sparingly soluble albuminoid obtained from peas, 
beans, etc.; and Conglutin, a substance closely related to legumin and to 
gliadin, but differing from them in some characters, obtained from almonds, 
are three vegetable albuminoids resembling casein. 

They are insoluble in pure water, readily soluble in dilute alkaline so- 
lutions, from which they are precipitated by acids and by rennet. 

Alkali albuminates— proteins of Hoppe Seyler — are formed when an 



366 GENERAL MEDICAL CHEMISTRY. 

albuminoid is dissolved in concentrated solutions of potassium and sodium 
hydrates; it is very probable that they are identical with serum and milk- 
casein. 

Acid albumins are substances obtained by precipitating solutions of 
albuminoids by the simultaneous addition of an acid and a large quantity 
of a neutral salt; they vary exceedingly in composition and proper- 
ties. 

Syntonin, parapeptone, is extracted from contractile tissues ; the 
same substance is formed by the action of dilute acids upon the albumi- 
noids, and as the first product of the action of the gastric juice, or of mix- 
tures of pepsin and dilute sulphuric acid upon albuminoids. It resembles 
serum casein closely, the only divergence in their properties being that 
syntonin is much more readily soluble in a 0.1 per cent, solution of hydro- 
chloric acid, and in faintly alkaline liquids. 

Peptones, albuminose, are the products of the action of the gastric 
and pancreatic juices upon albuminoids during the process of digestion. 

They are soluble in water, insoluble in alcohol and ether. Their 
watery solutions are neutral, are not precipitated by acids or alkalies, or 
by heat when the liquid is faintly acid. Alcohol precipitates them in 
white, casein-like flocks, which, if slowly heated to 90° while still moist, 
form a transparent, yellowish liquid, and, on cooling of the liquid, an 
opaque, yellowish, glassy mass. 

The most important character of the peptones is that they differ from 
other albuminoids in being capable of dialysis through animal membranes. 
Their presence in the blood has not been demonstrated, even in the portal 
vein; it is therefor probable that, almost immediately after their entrance 
into the circulation, they are reconverted into albuminoids resembling, 
although differing from, those from which they were derived. 

IV. — Coagulated albumins are obtained, as described above, from 
the soluble varieties by the action of acids, heat, alcohol, etc. They are 
insoluble in water, alcohol, solutions of neutral salts, dilute hydrochloric 
acid; difficultly soluble in dilute alkaline solutions. In acetic acid they 
swell up and dissolve slowly; from this solution they are precipitated by 
concentrated salt solution. Concentrated hydrochloric acid dissolves them 
with formation of syntonin. By the action of gastric juice, natural or 
artificial, they are converted first into syntonin, then into peptones. 

Fibrin is obtained when blood is allowed to coagulate or is whipped 
with a bundle of twigs. When pure it is at first a gelatinous mass, which 
contracts to a white, stringy, tenacious material, made up of numerous 
minute fibrils; when dried it is hard, brittle, and hygroscopic. It is in- 
soluble in water, alcohol, ether; in dilute acid it swells up and dissolves 
slowly and incompletely. When heated with water to +72°, or by con- 
tact with alcohol, it is contracted, and is no longer soluble in dilute acids, 
but soluble in dilute alkalies. In solutions of many neutral salts of six to 
ten per cent., it swells up and is partially dissolved; from this solution 
it separates on the addition of water, or upon the application of heat to 
+ 73°, or by acetic acid or alcohol. Moist fibrin has the curious property 
of decomposing oxygenated water with copious evolution of oxygen. 

Fibrin does not exist as such in the blood, and the method of its form- 
ation and of the clotting of blood has been the subject of a vast amount 
of experiment and argument; nor can the question be said to be definitely 
set at rest. In the light of the researches of Denis, Schmidt, and espe- 
cially of Hammarsten, it may be considered as almost proven that fibrin is 
formed from fibrinogen under favorable circumstances, and by a transfor- 



ALBUMINOIDS. 367 

mation which is not yet understood. Whether paraglobulin plays any 
part directly in the formation of fibrin or not, is still an open question. 

V. Amyloid is a pathological product, occurring in fine grains, re- 
sembling starch-granules in appearance, in the membranes of the brain 
and cord, in waxy and lardaceous liver, and in the walls of the blood-ves- 
sels. Its composition is that of the albuminoids, from which it differs in 
being colored red by iodine; violet or blue by iodine and sulphuric acid. 
Soluble in hydrochloric acid with formation of syntonin; and in alkalies. 
It is not attacked by the gastric juice, and is not as prone to putrefaction 
as the albuminoids. 

VI. Collagen. — Bony tissue is made up mainly of tricalcic phosphate, 
combined with an organic material called ossei?i, which is a mixture of 
collagen, elastin, and an albuminoid existing in the bone-cells. Collagen 
also exists in all substances which, when treated with water under the in- 
fluence of heat and pressure, yield gelatin. It is insoluble in cold water, 
but by prolonged boiling is converted into gelatin, which dissolves. It 
is dissolved by alkalies. 

Gelatin, obtained as above, from ossein, exists in the commercial pro- 
duct of that name, and in a less pure form in glue. When pure it is an 
amorphous, translucent, yellowish, tasteless substance, which swells up in 
cold water, without dissolving, and forms, with boiling water, a thick, 
sticky solution, which on cooling becomes, according to its concentration, a 
hard glassy mass or a soft jelly — the latter, even when the solution is very 
dilute. It is insoluble in alcohol and ether, but soluble, on warming, 
in glycerin; the solution in the last-named liquid forms, on cooling, a 
jelly which has recently been applied to various contrivances for copying 
writing. A film of gelatin impregnated with potassium dichromate be- 
comes hard and insoluble on exposure to sunlight — a property which has 
been utilized in photography. 

Elastin is obtained from elastic tissues by successive treatment with 
boiling alcohol, ether, water, concentrated acetic acid, dilute potash solu- 
tion and water. It is fibrous, yellowish; swells up in water and becomes 
elastic; soluble with a brown color in concentrated potash solution. It 
contains no sulphur, and on boiling with sulphuric acid yields glycocol. 

Chondrigen, a substance closely resembling collagen, existing in the 
cartilage and the tissues of lower animals, which differs from collagen in 
yielding chondrin when heated with water, under pressure. 

Chondrin is distinguished from gelatin by being precipitated by al- 
most all acids, including acetic; in not precipitating with tannin; and in 
yielding leucin in place of glycocol on boiling with sulphuric acid. 

Keratin is the organic basis of horny tissues, hair, nails, feathers, 
whalebone, epithelium, tortoise-shell, etc. It is probably not a distinct 
chemical compound, but a mixture of several closely related bodies. 

Mucin is a substance resembling the albuminoids, but containing no 
sulphur and existing in the different varieties of mucus, in certain patho- 
logical fluids, in the bodies of molluscs, in the saliva, bile, etc. Its 
solutions, like the fluids in which it occurs, are viscid. It is precipi- 
tated by acetic acid and by nitric acid, but is dissolved by an excess of 
the latter; it dissolves readily in alkaline solutions, and swells up in 
water, with which it forms a false solution. It is not coagulated by heat. 



368 GENERAL MEDICAL CHEMISTRY. 



SOLUBLE ANIMAL FERMENTS. 

Under this head are classed substances which are closely related to 
the albuminoid^ which exist in animal fluids, and which have the power 
of effecting peculiar changes in other organic substances. Prominent 
among them are pti/alin, pepsin, and pancreatin. 

Ptyalin is a substance closely resembling diastase in its characters 
and properties, existing in saliva. Like diastase, it converts starch into 
sugar. 

Pepsin is the albuminoid ferment of the gastric juice. Attempts 
to separate it without admixture of other substances have hitherto proved 
fruitless; nevertheless, mixtures containing it and exhibiting its charac- 
teristic properties more or less actively, have been obtained by various 
methods. The most simple is that of Wittich, which consists in macera- 
ting the finely divided mucous membrane of the stomach in alcohol for 
forty-eight hours, and afterward extracting it with glycerin; this forms 
a solution of pepsin, which is quite active and resists putrefaction well, 
and from which a substance containing the pepsin is precipitated *by a 
mixture of alcohol and ether. 

If pepsin is required in the solid form, it is best obtained by Briicke's 
method. The mucous membrane of the stomach of the pig is cleaned and 
detached from the muscular coat by scraping; the pulp so obtained is di- 
gested with dilute phosphoric acid at 38°, until the greater part of it is 
dissolved ; the filtered solution is neutralized with lime-water; the pre- 
cipitate is collected, washed with water, and dissolved in dilute hydro- 
chloric acid ; to this solution a saturated solution of cholesterin, in a 
mixture of four parts alcohol and one part ether, is gradually added ; 
the deposit so formed is repeatedly shaken with the liquid, collected on a 
filter, washed with water and then with dilute acetic acid, until all hydro- 
chloric acid is removed; it is then treated with ether and water: the former 
dissolves cholesterin and is poured off, the latter the pepsin; after several 
shakings with ether the aqueous liquid is evaporated at 38°, when it 
leaves the pepsin as an amorphous, grayish white substance; almost in- 
soluble in pure water, readily soluble in acidulated water, probably form- 
ing a compound with the acid, which possesses the property of converting 
albuminoids into peptones. 

The so-called pepsina jiorci is either the calcium precipitate obtained 
as described in the first part of the above method; or, more commonly, 
the mucous membrane of the stomach of the pig, scraped off, dried, and 
mixed with rice-starch. 

Pancreatin. — Under this name, substances obtained from the pancrea- 
tic secretion, and from extracts of the organ itself, have been described, 
and to some extent used therapeutically. They do not, however, con- 
tain all the ferments of the pancreatic juice, and in many instances are 
inert albuminoids. The actions of the pancreatic juice are various: 1st, 
it rapidly converts starch, raw or hydrated, into sugar; 2d, in alkaline 
solution — its natural reaction — it converts albuminoids into peptones; 3d, 
it emulsifies neutral fats; 4th, it decomposes fats, with absorption of 
water and liberation of glycerin and fatty acids. 

The pancreatic secretion probably contains a number of ferments — 
certainly two, probably three. The one of these to which it owes its pep- 
tone-forming power has been obtained in a condition of comparative 



ANIMAL COLORING MATTERS. 369 

purity by Kiihne, and called by him trypsin; in aqueous solution it 
digests fibrin almost immediately, but it exerts no action upon starch. 

The diastatic (sugar-forming) ferment of the pancreatic juice has not 
been separated, although a glycerin extract of the finely divided pancrea- 
tic tissue contains it, along with trypsin. 

ANIMAL COLORING MATTERS. 

Haemoglobin and its derivatives. — Hcemato-crystallin. — The 
coloring matter of the blood is a highly complex substance, resembling 
the albuminoids in many of its properties, but differing from them in 
being crystallizable and in containing iron. 

It exists in the red corpuscles, from which it is obtained by the follow- 
ing method: the blood is allowed to coagulate in a capsule and to remain 
at rest for twenty-four hours; the serum is decanted, the clot washed with 
water, cut into small pieces, and these again washed until the washings 
are not strongly precipitated by mercuric chloride; the clot is then ex- 
tracted with water at 30° — 40°, and the liquid filtered and collected in a 
cylinder surrounded with ice. A known fraction of the solution is 
treated with alcohol, gradually added from a burette during constant 
stirring of the solution, until a slight precipitate is formed; to the re- 
mainder of the aqueous liquid a somewhat smaller proportion of alcohol 
is then added than is required to form a precipitate; the mixture is placed 
in a freezing mixture, where, after some hours, an abundant crop of 
crystals separates; this is collected on a filter, washed first with water 
containing alcohol, and then with iced water, and finally dried below 0°. 

Haemoglobin exists in two conditions of oxidation; in the form in 
which it exists in arterial blood, and as obtained above, it is loosely com- 
bined with a certain quantity of oxygen, and is known as oxyhemoglobin. 
The mean of many nearly concording analyses shows its composition to be 
C 600 H 960 N 154 FeS 3 O ]70 . When obtained from the blood of man and from 
that of many of the lower animals, it crystallizes in beautiful red prisms 
or rhombic plates; that from the blood of the squirrel in hexagonal plates; 
and that from the guinea-pig in tetrahedra. The crystals are always 
doubly refracting. It may be dried in vacuo at 0°; when it contains 
three to four per cent, of water of crystallization, which it loses at 110° — 
120°; if thoroughly dried below 0°, it may be heated to 100° without de- 
composition, but the presence of a trace of moisture causes its decompo- 
sition at a much lower temperature. Its solubility in water varies with the 
species of animal from whose blood it was obtained; thus, that from the 
guinea-pig is but sparingly soluble, while that from the pig is very solu- 
ble in water. It is also dissolved unchanged bv verv weak alkaline solu- 
tions, but is decomposed by acids or salts having an acid reaction. 

Haemoglobin, or reduced haemoglobin, is formed from oxyhemoglo- 
bin in the economy during the passage of arterial into venous blood, and 
by the action of reducing agents, or by boiling its solution at 40° in the 
vacuum of the mercury pump. 

Oxyhemoglobin is of a much brighter color than the reduced, and 
has a different absorption spectrum. The spectrum of oxyhemoglobin 
has two bands between D and E; the one nearer D being the narrower, 
darker, and more sharply defined of the two, it is also the last to disap- 
pear on dilution; beyond a certain degree of concentration of the solu-r 
tion the two bands unite together, forming a single, broad, dark band, 
24 



370 GENERAL MEDICAL CHEMISTRY. 

extending beyond both D and E. The spectrum of hemoglobin, on the 
other hand, has but one band, much broader and fainter than either of 
the oxyhemoglobin bands, extending from D to about as near E as the 
border of the oxyhemoglobin band nearest that line. 

Hsemoglobin, in contact with oxygen or air, is immediately con- 
verted into oxyhemoglobin. With carbon monoxide it forms a com- 
pound resembling oxyhemoglobin in the color of its solution, but in 
which the carbon dioxide cannot be replaced by oxygen ; for which 
reason hemoglobin, once combined with carbon monoxide, becomes per- 
manently unfit to fulfil its function in respiration. The spectrum of the 
carbon monoxide compound resembles somewhat that of oxyhemoglobin, 
except that the bands are more nearly equal in width and intensity, and 
are rather nearer the violet end of the spectrum. 

When a solution of oxyhemoglobin is boiled, it becomes turbid, and 
a dirty, brownish red coagulum is deposited; the hemoglobin has been de- 
composed into an albuminoid (or mixture of albuminoids), called by Pre}'er 
globin, and hmmatin. The latter, at one time supposed to be the blood-color- 
ing matter, is a blue-black substance, having a metallic lustre and incapa- 
ble of crystallization; it is insoluble in water, alcohol, ether, and dilute 
acids; soluble in alkaline solutions. It has the composition C c8 H 70 N 8 Fe 2 O 1() 
(?). Although itself uncrystallizable, hematin combines with hydro- 
chloric acid to form a compound which crystallizes in rhombic prisms, 
and which is identical with the earliest known crystalline blood-pigment, 
hcemin, or Teichmann's crystals. 

When reduced hematin is decomposed as above, in the absence of 
oxygen, hematin is not produced, but a substance identical with that 
called reduced hoematin, and called by Hoppe-Seyler hcemocromogen. 

Biliary pigments. — There are certainly four, and probably more, 
pigmentary bodies obtainable from the bile and from biliary calculi, 
some of which consist in great part of them. 

Bilirubin, C 32 H 36 N 4 6 , is, when amorphous, an orange-yellow powder, 
and when crystalline, in red rhombic prisms. It is sparingly soluble in 
watery alcohol, and ether ; readily soluble in hot chloroform, carbon di- 
sulphide, benzene, and in alkaline solutions. When treated with nitric 
acid containing nitrous acid, or with a mixture of concentrated nitric 
and sulphuric acids, it turns first green, then blue, then violet, then red, 
and finally yellow. This reaction, known as Gmelin's, is very delicate, 
and is used for the detection of bile-pigments in icteric urine and in other 
fluids. 

JBiliverdin, C 32 H 36 N 4 8 , is a green powder, insoluble in water, ether, 
and chloroform; soluble in alcohol and in alkaline solutions. It exists in 
green biles, but its presence in yellow biles or biliary calculi is doubtful. 
It responds to Gmelin's test. In alkaline solution it is changed after a 
time into biliprasin. 

JBilifuscin, C 16 H 20 N 2 O 4 — obtained in small quantity from human gall- 
stones, is an almost black substance, sparingly soluble in water, ether, and 
chloroform; readily soluble in alcohol and in dilute alkaline solutions. 
Its existence in the bile is doubtful. 

Biliprasin, C 1C H 22 N 2 6 (?), exists in human gall-stones, in ox-gall, 
and in icteric urine. It is a black, shining substance, insoluble in water, 
ether, and chloroform; soluble in alcohol and in alkaline solutions. 

Urobilin, or hydrobilirubin, C 32 H 40 N 4 O 7 . Under the name urobilin, 
Jaffe" described a substance which he obtained from dark, febrile urine, 
and which he regarded as the normal coloring matter of that fluid; subse- 



ANIMAL COLORING MATTERS. 371 

quently he obtained it from dog's bile and from human bile, from gall- 
stones and from faeces. Stereobilin from the faeces is identical with uro- 
bilin. 

Urinary pigments. — Our knowledge of the nature of the substances 
to which the normal urinary secretion owes its color is exceedingly un- 
satisfactory. Jaffe in his discovery of urobilin shed but a transient light 
upon the question, as that substance has been found to exist in but a 
small percentage of the normal urines examined, although they certainly 
contain a substance readily convertible into it ; a great deal of confusion 
has also been introduced into the subject by the description, especially 
by Thudichum, of ill-defined mixtures as urinary pigments. Besides the 
substance convertible into urobilin, and sometimes urobilin itself, human 
and mammalian urines contain at least one other pigmentary body: 
uroxanthin, or indigogen. This substance was formerly considered as 
identical with indican, a glucoside existing in plants of the genus Isatis, 
which, when decomposed, yields, among other substances, indigo-blue. 
Uroxanthin, however, differs from indican in that the former is not de- 
composed by boiling with alkalies, and does not yield any glucose-like 
substance on decomposition ; the latter is almost immediately decom- 
posed by boiling alkaline solutions, and, under the influence of acids and 
of certain ferments, yields, besides indigo blue, indiglucm, a sweet, non- 
fermentable substance, which reduces Fehling's solution. 

Uroxanthin is a normal constituent of human urine, but is much in- 
creased in the first stage of cholera, in cases of cancer of the liver, 
Addison's disease, and intestinal obstruction. It has also been detected 
in the perspiration. 

The presence of uroxanthin in the urine is indicated by the following 
tests: 1st, ten cubic centimetres of the urine are treated with an equal 
volume of hydrochloric acid, and then with a saturated solution of chloride 
of lime, added guttatim; the solution is colored, according to the amount 
of uroxanthin present, red, violet, green, or blue; on being filtered it 
leaves a blue deposit on the paper; 2d, three or four cubic centimetres 
of concentrated hydrochloric acid are placed in a test-tube, and thirty to 
forty drops of urine added; it assumes a red, violet, or blue color; 3d, the 
urine is warmed with two parts of nitric acid to 60° — 70°, and shaken 
with chloroform; the latter fluid is colored violet-blue, and, if examined 
by the spectroscope, shows an absorption-band between and D. 

Melanin is the black pigment of the choroid, melanotic tumors, skin 
of the negro; and occurs pathologically in the urine, and deposited in the 
air-passages. 



372 GENERAL MEDICAL CHEMISTRY. 



SILICON. 
Si 28 

Also known as silicium, resembles carbon, and occurs in three allo- 
tropic forms: Amorphous silicon, formed when silicon chloride is passed 
over heated potassium or sodium, is a dark brown powder, heavier than 
water; when heated in air it burns with a bright flame to the dioxide. 
It dissolves in potash and in hydrofluoric acid, but is not attacked by 
other acids. Graphitoid silicon is obtained by fusing potassium fluosili- 
cate with aluminium. It forms hexagonal plates, of sp. gr. 2.49, which 
do not burn when heated to whiteness in oxygen, but may be oxidized at 
that temperature by a mixture of potassium chlorate and nitrate. It dis- 
solves slowly in alkaline solutions, but not in acids. Crystallized silicon, 
corresponding to the diamond, forms crystalline needles, which are only 
attacked by a mixture of nitric and hydrofluoric acids. 

Silicon, although closely related to carbon, exists in nature in but few 
compounds; it has been caused to form artificial combinations, however, 
which indicate its possible capacity to exist in substances corresponding 
to those carbon compounds vulgarly known as organic, e.g., silicichlorO' 
form and silicibromoform, SiHCl 3 and SiHBr 3 . 

Hydrogen silicide, SiH 4 — is obtained as a colorless, insoluble, spon- 
taneously inflammable gas, by passing the current of a galvanic battery 
of twelve cells through a solution of common salt, using a plate of alu- 
minium, alloyed with silicon, as the positive electrode. 

Silicon chloride, SiCl 4 — a colorless, volatile liquid, having an irri- 
tating odor; sp. gr. 1.52; boils at 59°; formed when silicon is heated to 
redness in chlorine. 

Silicic oxide — Silicic anhydride — Silex — Si0 2 — is the most impor- 
tant of the compounds of silicon. It exists in nature in the different 
varieties of quartz, and in the rocks and sands containing that mineral, 
in agate, carnelian, flint, etc. Its purest native form is rock crystal; its 
hydrates occur in the opal, and in solution in natural waters. When crys- 
tallized it is fusible with difficulty; when heated to redness with the al- 
kaline carbonates it forms silicates, which solidify to glass-like masses on 
cooling. It unites with water to form a number of acid hydrates. The 
normal hydrate, Si0 4 H 4 , has not been isolated, although it probably exists 
in the solution obtained by adding an excess of hydrochloric acid to a 
solution of sodium silicate. A gelatinous hydrate, soluble in water and 
in acids and alkalies, is obtained by adding a small quantity of hydro- 
chloric acid to a concentrated solution of sodium silicate. 

Hydrofluosilicic acid, SiF 6 H 2 — is obtained in solution by passing 
the gas disengaged by gently heating a mixture of equal parts of fluor- 
spar and pounded glass, and six parts of sulphuric acid, through water, 
the disengagement tube being protected from moisture by a layer of 
mercury. It is used in analysis as a test for potassium and sodium. 



MOLYBDENUM. 373 

VII. MOLYBDENUM GROUP. 
Molybdenum, Mo, 96; Tungsten, W, 184; Osmium, Os, 200. 

The position of this group is doubtful; osmium forms an oxide which 
is basic in character, and also exists in a sulphite, and it consequently be- 
longs to the next class; nevertheless, the relations of its compounds to 
those of tungsten and molybdenum are such as to induce us to place it in 
the same group with them. It is probable that the lower oxides of tung- 
sten and molybdenum will be found to possess basic characters, in which 
case the entire group should be transferred to the following class. 

Molybdenum — isolated with difficulty by reduction of its oxides, 
which are obtained from a native sulphide. 

Molybdic anhydride, Mo0 3 — unites with water to form a number of 
acids, the ammonium salt of one of which is a sensitive reagent for phos- 
phoric acid. The conjugate phosphomolybdic acid is a valuable reagent 
for the alkaloids. 

Tungsten — 'Wolfram — occurs associated with tin. 

Tungstic anhydride, W0 3 — a yellow powder which unites with water 
to form several acid hydrates, one of which, metatungstic acid, W 4 3 H 2 , 
is used as a test for alkaloids, as are also the conjugate silico-tungstic and 
phospho-tungstic acids. Sodium tungstate is used to render fabrics non- 
inflammable. 

Osmium is a rare element occurring with iridium in platinum ores. 
The oxide, 0s0 4 , known as osmic acid, is used as a staining agent in 
histological laboratories. Its vapor is intensely irritating. 



374 GENERAL MEDICAL CHEMISTRY. 



class m. 

Elements whose Oxides Unite with Water, some to form Bases, 
others to form adds. which form oxysalts. 

I. GOLD GROUP. 
GOLD Au 197 

This, the only member of the group, forms two series of compounds: 
in one, AuOl, it is univalent; in the other, AuCl 3 , trivalent. Its hydrate, 
auric acid, Au (OH) 3 , corresponds to the oxide Au 2 3 . Its oxysalts are 
unstable. 

It is yellow or red by reflected light, green by transmitted light, red- 
dish purple when finely divided; not very tenacious; very malleable and 
ductile; softer than silver; fuses at about 1200°; sp. gr. 19.258 when cast, 
19.367 when hammered. 

It is not acted upon by water, air, oxygen, or single mineral acids. 
It combines directly with chlorine, bromine, iodine, phosphorus, anti- 
mony, arsenic, and mercury. It dissolves in nitro-muriatic acid. It is 
oxidized on contact of air by alkalies in fusion. 

Aurous chloride, AuCl — a pale yellow, insoluble powder formed 
when auric chloride is heated to 200°; decomposed at higher tempera- 
tures into chlorine and gold. 

Auric chloride — Gold trichloride — AuCl 3 — obtained by dissolving 
gold in aqua regia, evaporating at about 100°, and purifying by crystal- 
lization from water. Deliquescent yellow prisms, very soluble in water, 
alcohol, and ether. Readily decomposed, with separation of gold, on con- 
tact with phosphorus or with reducing agents. Its solution, treated with 
the chlorides of tin, deposits the flocculent purple of Cassius. With 
the alkaline chlorides it forms permanent double chlorides — chloraurates. 
It stains the skin purple. 

Sodium chloraurate and aurous iodide have been used medicinally. 
The trichloride is an active poison and a corrosive, being decomposed by 
organic matter with deposition of gold and liberation of chlorine. 

Analytical characters. — Hydrogen sulphide — from neutral or acid 
solution; blackish brown precipitate in the cold; insoluble in nitric and 
hydrochloric acids, soluble in aqua regia and in yellow ammonium sulphy- 
drate. Stannous chloride, with a little chlorine water, purple-red pre- 
cipitate, insoluble in hydrochloric acid. Ferrous sulphate, brown de- 
posit, which assumes the lustre of gold when dried and burnished. 



II. IRON GROUP. 

Chromium, Cr, 52.4; Manganese, Mn, 55.2; Iron, Fe, 56. 

These elements form two series of compounds; in one a single atom 
is divalent, as in Fe"Cl„; in the other, two atoms combined form a hexava- 
lent group, as in (Fe) vi Cl 6 . The oxides M0 3 are anhydrides, correspond- 
ing to which are acids and salts. 



CHROMIUM. 375 



CHROMIUM. 
Cr 52.4 

The element is isolated with difficulty from its oxide or chloride. It 
is steel-gray, hard, brilliant, magnetic at low temperatures; sp. gr. 6.8 at 
20°. It combines with oxygen only at a red heat; is not attacked by 
acids, except hydrochloric acid; is readily attacked by alkalies. 

Chromium sesquioxide — Green oxide — Cr 2 3 — is obtained, amor- 
phous, by calcining a mixture of potassium dichromate and starch, or 
crystallized by heating neutral potassium chromate to redness in chlorine. 

It is green; insoluble in water, acids, and alkalies; fusible with diffi- 
culty, and not decomposed by heat; not reduced by hydrogen. At a 
red heat in air, it combines with alkaline hydrates and nitrates to form 
chromates. It forms two series of salts, the terms of one of which are 
green, those of the other, violet. The alkaline hydrates separate a blu- 
ish green hydrate from solutions of the green salts, and a bluish violet 
hydrate from those of the violet salts. 

Chromium green, or emerald green, is a brilliant green hydrate, formed 
by decomposing a double borate of chromium and potassium by water. 
It is used in the arts as a substitute for the arsenical greens, and is non- 
poisonous. 

Chromic anhydride, Cr0 3 — improperly called chromic acid, is pre- 
pared by slowly adding one and one-half parts of strong sulphuric acid to 
one part of a concentrated solution of potassium dichromate, draining the 
crystals on a porous tile, and purifying by solution in water, exact pre- 
cipitation by barium chromate, and crystallization over sulphuric acid. 

It forms deliquescent, crimson prisms, very soluble in water, soluble 
in alcohol. It is a powerful oxidant, capable of igniting strong alcohol. 

The true chromic acid has not been isolated, but salts corresponding to 
three acid hydrates are known: Cr0 4 H 2 = chromic acid / Cr 2 7 H 2 — di- 
chromic acid ; Cr 3 ^TL^trichromic acid. 

Chlorides. — Two chlorides and one oxvchloride of chromium are 
known. Chromous chloride, CrCl 2 , is a white solid, soluble with a blue 
color in water. Chromic chloride, (Cr 2 )Cl 6 , forms large, red crystals, in- 
soluble in water when pure. 

Sulphates. — A violet sulphate crystallizes in octahedra, (S0 4 ) 3 (Cr) 2 
+ 15 Aq., and is very soluble in water; at 100° it is converted into a 
green salt, (S0 4 ) 3 (Cr) 2 + 5 Aq., soluble in alcohol, which at higher temper- 
atures is converted into the red, insoluble, anhydrous salt. Chromic sul- 
phate forms double sulphates, containing 24 Aq., with the alkaline sul- 
phates (see Alums). 

Analytical Characters. — Chromous Salts: Potash, brown pre- 
cipitate; Ammonium hydrate, greenish white precipitate; Alkaline sul- 
phides, black precipitate; /Sodium phosphate, blue precipitate. 

Chromic Salts. — Potash, green precipitate; excess of precipitant 
forms green solution, from which sesquioxide separates on boiling; Am- 
monium hydrate, greenish gray precipitate; Ammonium sulphydratc, 
greenish precipitate. 

Chromates. — Hydrogen sidphide, in acid solution, brownish color, 
changing to green; Ammonium sulphydrate, greenish precipitate; Ba- 
rium chloride, yellowish precipitate; Silver nitrate, brownish red precipi- 



376 GENERAL MEDICAL CHEMISTRY. 

tate, soluble in nitric acid and in ammonia; Lead acetate, yellow pre- 
cipitate, soluble in potash, insoluble in acetic acid. 

Action on the economy. — Chromic anhydride oxidizes organic 
substances, and is used as a caustic. 

The chromates, especially potassium dichromate (q. v.), are irritants, 
and have a distinctly poisonous action as well. Workmen handling the 
dichromate are liable to a form of chronic poisoning. 

In acute chromium-poisoning, emetics, and subsequently magnesium 
carbonate in milk, are to be given. 



MANGANESE. 
Mn 55.2 

A grayish, brittle metal, hard, fusible with difficulty; sp. gr. 7.138 — 
7.206; obtained by reduction of its oxides. When pure, it is not altered 
by dry air in the cold, but is superficially oxidized when heated. It de- 
composes water, especially when heated, and dissolves in dilute acids. 

Oxides. — Manganese forms six oxides, or compounds representing 
them: Manganous oxide, MnO; Mangano so -manganic oxide, Mn 3 4 ; 
Manganic oxide, Mn 2 3 ; Permanganic oxide, Mn0 2 ; Manganic anhy- 
dride, Mn0 3 ; Permanganic anhydride, Mn 2 7 . 

Permanganic Oxide. — Manganese dioxide, Blade oxide of manga- 
nese, Mn0 2 , exists in nature as pyrolusite, the principal ore of manganese, 
in steel-gray or brownish, imperfectly crystalline masses. 

At a red heat it loses 12 per cent, of oxygen, and is converted into 
Mn 3 4 , which, at a w 7 hite heat, yields a further quantity of oxygen, leav- 
ing MnO. Heated with sulphuric acid, it gives off oxygen and forms 
manganous sulphate. With hydrochloric acid, it yields manganous 
chloride, water, and chlorine. With sulphuric and oxalic acids, it forms 
manganous sulphate, water, and carbon dioxide. It forms three hy- 
drates, one of which corresponds to a series of salts, called manganites, 
Mn 6 0„M 2 . 

Neither manganic anhydride, nor manganic acid, Mn0 4 H 2 , have 
been separated; they are, however, represented by well-defined salts, the 
manganates, Mn0 4 M 2 . 

Permanganic anhydride is an unstable, green liquid, and an active 
oxidant. Permanganic acid, Mn0 4 H, is obtained in solution by decom- 
position of its barium salt, by sulphuric acid (see Potassium permanga- 
nate). 

Salts. — Like iron, manganese forms two series of salts: Manganous 
salts, containing Mn"; and manganic salts, containing (Mn 2 ) vi ; the former 
are colorless or pink, and soluble in water; the latter are quite unstable. 

Manganous Sulphate, So 4 Mn. — is formed by the action of sulphuric 
acids upon the oxides of manganese. Below 6° it crystallizes with 7 Aq., 
and is isomorphous with ferrous sulphate; between 7° and 20° it forms 
crystals with 5 Aq., and is isomorphous with cupric sulphate; between 
20° and 30° it crystallizes with 4 Aq. It is rose-colored, darker as the 
proportion of Aq. increases, soluble in water, insoluble in alcohol. With 
the alkaline sulphates it forms double salts with 6 Aq. 

Analytical Characters. — Manganous. — Potash. — White precipi- 
tate, turning brown. Alkaline carbonates, white precipitate. Ammo- 
nium sulphydrate, flesh-colored precipitate, soluble in acids, sparingly 



iron. 377 

soluble in excess of precipitant. Potassium ferrocyanide, reddish white 
precipitate, soluble in hydrochloric acid. Potassium f err icy anide, brown 
precipitate. Potassium cyanide, rose-colored precipitate, forming brown 
solution in excess. 

Manganic. — Hydrogen sulphide, precipitate of sulphur. Ammo- 
nium sulphydrate, flesh- colored precipitate. Potassium ferrocyanide, 
greenish precipitate. Potassium ferricy anide ^ brown precipitate. Potas- 
sium cyanide, light brown precipitate. 

The Manganates are green salts, whose solutions are only stable in 
presence of excess of alkali, and turn brown when diluted and acidulated. 
The Pekmanganates form red solutions, which are decolorized by redu- 
cing agents and by many organic substances; sulphurous acid turns them 
green. 



IRON. 
Fe 56 

The principal ores of iron are: red haematite, sesquioxide; spathic ore, 
ferrous carbonate; bog ore, ferrous carbonate, mixed with clay; oolitic 
iron and brown haematite, hydrates of the sesquioxide; magnetic or black 
ore, pyrites, and meteoric iron. 

In wopking the ores, reduction is first effected in a blast-furnace, into 
which alternate layers of ore, coal, and limestone are fed from the top, 
while air is forced in from below. In the lower part of the furnace car- 
bon dioxide is produced at the expense of the coal; higher up it is re- 
duced by the incandescent fuel to carbon monoxide, which at a still 
higher point reduces the ore; the fused metal so liberated collects at the 
lowest point under a layer of slag, and is drawn off to be cast as pig iron. 
This product is then purified by burning out impurities in the process 
known as puddling. 

Iron is used in the arts in three forms: Cast iron, a brittle, crystalline 
materia], containing carbon, silicon, phosphorus, and sulphur. Wrought 
iron, a fibrous, tough variety, freed to a great extent from the impuri- 
ties of cast iron, although not chemically pure. Steel is iron combined 
with a small quantity of carbon. It is prepared either by cementation, 
which consists of causing a pure iron to combine with carbon; or by the 
Pessemer method, which consists in burning the proper quantity of car- 
bon out of cast iron. Pure iron is obtained by heating ferric oxide nearly 
to redness in a current of hydrogen; this is the ferrum redactum (U. S., 
Br.). The purest forms of commercial iron are those used in piano-strings, 
electro- magnets, and the teeth of carding-machines. The finely divided 
iron by alcohol is produced by mechanical division and levigation in 
alcohol. 

Pure iron is quite soft; fuses at about 1600°; crystallizes in cubes or 
octahedra; is very tenacious; sp. gr. 7.25 — 7.9. 

Iron is not altered by dry air at ordinary temperatures; at a red heat 
it is oxidized; in damp air it is converted into a hydrate, known as rust. 
Tin plate is sheet iron coated with tin ; galvanized iron is protected by a 
coating of zinc. Iron unites directly with chlorine, bromine, iodine, sul- 
phur, and the elements of the phosphorus group. Hydrochloric acid 
dissolves it as ferrous chloride, while hydrogen is liberated. Heated 
with strong sulphuric acid, it gives off sulphur dioxide; with the dilute 



378 GENERAL MEDICAL CHEMISTRY. 

acid, hydrogen is given off and ferrous sulphate formed. Dilute nitric 
acid dissolves iron, but the concentrated acid renders it passive, when it 
1 is no longer attacked by a dilute acid until the passive condition is de- 
stroyed by contact with platinum, silver, or copper, or by heating to 40°. 

Oxides. — Five oxides of iron are known, three of which are of interest. 

Ferrous Oxide, FeO — is formed by heating ferric oxide in carbon 
mon- or dioxide. Its hydrate, FeH 2 2 , is a greenish white substance, 
formed when a ferrous salt is decomposed by an alkaline hydrate. 

Ferric Oxide — Sesquioxide or Peroxide of iron — Fe 2 . — When fer- 
rous sulphate is heated, it turns white by loss of Aq.; then yellow, owing 
to formation of an oxy hydrate; then brick -red, when it has been converted 
into ferric oxide; another product being Nordhauseii sulphuric acid. 

Under the names colcothar, red crocus, jeweller's rouge, and Venetian 
red, it is used as a polishing material and as a pigment. 

The normal hydrate — Ferri peroxidum humidum (U. S., Br.) — (Fe 2 ) 
H 6 6 — is a brown, gelatinous precipitate, formed when an alkali is added 
to a ferric salt. When dried at 100° it loses 2H 2 0, and is converted into 
Ferri peroxidum hydratum (U. S., Br.), (Fe 2 )0 2 ,H 2 O 2 . Ferric hydrate is 
not precipitated in presence of fixed organic acids, or of sugar in sufficient 
quantity. Under water it is converted into an oxyhydrate, which is in- 
capable of forming ferrous arsenate with arsenic trioxide. 

A peculiar modified ferric hydrate, (Fe 2 )0 2 H 2 2 , is formed by drying 
the ordinary hydrate in vacuo and boiling it seven- or eight hours in 
water; after washing, it is almost insoluble in nitric and hydrochloric acids, 
and gives no Prussian blue reaction; it dissolves in dilute acetic acid, 
the solution being reddish and appearing turbid by reflected light. 

Recently precipitated ferric hydrate dissolves in solutions of ferric 
chloride or acetate, and the solutions, by dialysis, lose their acid, leaving 
in the dialyser a dark red solution of ferric hydrate. The dialysed iron 
so obtained is coagulated by heat, by sulphuric acid, alkalies, and many 
salts. 

Ferric Anhydride — Fe 2 3 , and Ferric Acid — Fe 2 4 H 2 , are un- 
known, but are represented by potassium ferrate, Fe 2 4 K 2 . 

Sulphides. — Eight sulphides of iron are known, of which three are 
of interest. 

Ferrous Sulphide — Protosidphide — FeS — is formed: 1st, by bring- 
ing a mixture of sulphur and iron filings into a red-hot crucible; 2d, by 
pressing roll-sulphur upon white-hot iron; 3d, by precipitating a ferrous 
salt with an alkaline sulphydrate. The dry methods form brownish, 
brittle, fusible, magnetic masses; the wet method yields a black powder. 

It is not decomposed by heat; is oxidized by damp air; is decomposed 
by dilute sulphuric acid, with formation of ferrous sulphate and hydrogen 
sulphide. It occurs in the faeces of persons taking chalybeate waters and 
preparations of iron. 

Ferric Sulphide — Sesquisulphide — Fe 2 S 3 — occurs in nature in copper 
pyrites, and is formed when the disulphide is heated to redness. 

Iron Disulphide — Martial pyrites — FeS 2 — occurs in yellow and white 
pyrites, which are extensively used in the manufacture of sulphuric acid. 

Chlorides. — Two chlorides of iron are known: FeCl 2 and (Fe 2 )Cl G . 

Ferrous Chloride, FeCl 2 — is formed when iron is heated to redness 
in dry hydrochloric acid, or with sal-ammoniac, as an anhydrous, yellow- 
ish, crystalline, volatile, and very soluble substance. A hydrated com- 
pound, FeCl 2 + 4Aq., is formed by solution of the anhydrous chloride, or 
by solution of iron in hydrochloric acid. It crystallizes in greenish, ob- 



IRON. 379 

lique rhombic prisms; loses its water when heated without contact of 
air; heated in air it is converted into ferric chloride and an oxychloride. 

Ferric Chloride — Sesquichloride — Perchloride — Ferri chloridum 
(U. S.) — Fe 2 Cl 6 — is obtained anhydrous by heating iron in chlorine; in 
violet, volatile, deliquescent plates. The hydrated compound, Fe 2 Cl 6 -f 
4Aq., is formed: 1st, by solution of the anhydrous; 2d, by dissolving 
iron in aqua regia; 3d, by dissolving hydrated ferric oxide in hydro- 
chloric acid; 4th, by the action of chlorine or of nitric acid on solution 
of ferrous chloride; it is prepared pharmaceutically by the last method. 

It forms yellow, nodular masses, or rhombic plates, very soluble in 
water, soluble in alcohol and ether. The Liq. ferri chloridi (U. S.), or 
Liq. ferri per 'chloridi (Br.), is an aqueous solution containing excess of 
acid. The Tinct. ferri chloridi (U. S.) is the liquor diluted with alcohol, 
and contains ethyl chloride and ferrous chloride. 

Bromides. — These are similar in composition to the chlorides. Fer- 
rous bromide, FeBr 2 , is formed by the action of bromine on excess of 
iron in presence of water. Ferric bromide, Fe 2 Br 6 , is obtained by the 
action of excess of bromine on iron. 

Iodides. — Ferrous iodide — Ferri iodidum (Br.) — Fel 2 — is obtained 
with 4Aq., by adding iodine to excess of iron under warm water until 
the solution is pale green. Ferric iodide, Fe 2 I 6 , is formed by the action 
of excess of iodine on iron. 

Salts. — Ferrous Sulphate — Protosulphate — Green vitriol — Cop- 
peras — Ferri sulphas (U. S., Br.) — S0 4 Fe — is obtained by oxidation of 
the sulphide remaining in the manufacture of sulphuric acid, and as a 
by-product in other processes. When required pure, it is prepared by 
dissolving iron in dilute sulphuric acid, and purifying by crystallization. 

It crystallizes in oblique, rhombic prisms with 7 Aq. ; it loses 6 Aq. at 
100°, and the last Aq. at 300°; at a red heat it is decomposed into ferric 
oxide, and sulphur di- and trioxides. It is soluble in water, insoluble in 
alcohol. By exposure to air it is gradually converted into a basic ferric 
sulphate, (S0 4 ) 3 (Fe 2 ),5Fe 2 3 . 

Ferric Sulphates are quite numerous, and are formed by oxidation 
of ferrous sulphate under different conditions. • The normal sulp>hate, 
(S0 4 ) 3 (Fe 2 ), is formed by treating ferrous sulphate solution with nitric 
acid, and evaporating after addition of one molecule of sulphuric acid for 
each two molecules of ferrous sulphate; its solution is the Liq. ferri 
tersulphatis (U. S.). Among the basic sulphates is one prepared by a 
process similar to the above, using half the quantity of sulphuric acid, 
which exists in Liq. ferri subsulphatis (U. S.), or MonseVs solution. 

Ferric sulphate forms alums with the alkaline sulphates. 

Ferrous Nitrate, (N0 3 ) 2 Fe — a greenish, unstable salt, formed by 
double decomposition between barium nitrate and ferrous sulphate; or 
by the action of nitric acid on ferrous sulphide. 

Ferric Nitrates. — The normal nitrate, (N0 3 ) 6 (Fe 2 ), is formed along 
with ferrous nitrate by solution of iron in nitric acid. The Liq. ferri 
nitratis (U. S.), or Liq. ferri per nitratis (Br.), contains ferric nitrate, and 
is made with an acid of sp. gr. 1.115. It crystallizes in rhombic prisms 
with 18 Aq. or in cubes with 12 Aq. When iron is dissolved in nitric 
acid to saturation, basic nitrates are formed, which prevent crystallization 
of the normal salt. 

Triferrous Phosphate, (P0 4 ) 2 Fe 3 — a white precipitate formed by 
adding disodic phosphate to a solution of a ferrous salt. By exposure to 
air it turns blue, a part being converted into ferric phosphate; the ferri 



380 GENERAL MEDICAL CHEMISTRY. 

phosphas (U. S., Br.) is such a mixture of the two salts. It is insoluble 
in water, sparingly soluble in water containing- carbonic and acetic acids. 

A phosphate of iron, capable of turning blue, occurs in the lungs in 
phthisis, in blue pus, and in long-buried bones. 

Ferric Phosphate, (P0 4 ) 2 (Fe 2 ) — is formed by the action of an alka- 
line phosphate on ferric chloride. It is soluble in hydrochloric, nitric, 
citric, and tartaric acids; insoluble in phosphoric acid. 

Ferric Pyrophosphate, (P 2 7 ) 3 (Fe 2 ) 2 — is formed by decomposition 
of a ferric salt by sodium pyrophosphate; an excess of the sodium salt 
dissolves the precipitate when warmed, and on evaporation leaves scales of 
a double salt, (P 2 7 ) 3 (Fe 2 ) 2 , (P 2 O 7 ) 2 Na ? + 20Aq. A similar ammonium salt, 
accompanied by ferric citrate, exists in the ferri pyrophosphas (U. S.). 

Ferrous Acetate, (C 2 H 3 2 ) 2 Fe — is formed by decomposition of fer- 
rous sulphate by calcium acetate. It crystallizes in soluble, silky needles. 

Ferric Acetates. — The normal salt, (C 2 H 3 2 ) e ,(Fe 2 ), is obtained by 
adding slight excess of ferric sulphate to lead acetate, and decanting after 
twenty-four hours. It is dark red, uncrystallizable, very soluble in alco- 
hol and in water. If its solution be heated it darkens suddenly, gives off 
acetic acid, and contains a basic acetate; when boiled it loses all its acetic 
acid and deposits ferric hydrate; when heated in closed vessels to 100°, 
and treated with a trace of mineral acid, it deposits the modified ferric 
hydrate. 

Ferrous Carbonate, C0 3 Fe — is obtained in the hydrated form by 
adding an alkaline carbonate to a ferrous salt ; on exposure to air it 
turns red from formation of ferric hydrate. It is insoluble in pure water, 
but soluble in water containing carbonic acid, probably as a bicarbonate, 
in which form it exists in mineral waters. The ferri earbonas saccharata 
(Br.) is this salt, to which sugar is added to delay decomposition ; the 
ferri subcarbonas (U. S.) is ferrous hydrate. 

Ferrous Lactate — Ferri lactas (U.S.) — (C 3 H & 3 ) 2 Fe-j-3Aq. — is 
formed by dissolving iron filings in lactic acid. It crystallizes in light 
yellow needles, soluble in water, insoluble in cold alcohol ; permanent in 
air when dry. 

Ferrous OxALATE-r-JF^rW oxalas (U. S.) — C 2 4 Fe + 2Aq. — is formed 
by dissolving iron in solution of oxalic acid. It is a bright yellow, crystal- 
line powder, sparingly soluble in hot water. 

Ferrous Tartrate, C 4 H 4 6 Fe-f 2Aq. — a white, crystalline powder, 
formed by dissolving iron in hot, strong solution of tartaric acid. 

Ferric Tartrate, (C 4 H 4 6 ) 3 (Fe 2 ) -f3Aq. — a dirty yellow, amorphous 
mass, obtained by dissolving recently precipitated ferric hydrate in tar- 
taric acid, and evaporating below 50°. Its solution is not precipitated by 
alkalies or alkaline carbonates. 

A number of double tartrates, containing the group (Fe 2 2 )" are also 
known. Such are : Ferrico- amnionic tartrate; ferri et ammonii tartras 
(U.S.), (C 4 H 4 6 ) 2 (Fe 2 2 ),(NH 4 ) 2 + 4Aq., and Ferrico-potassic tartrate; 
ferri et potassii tartras (U. S.), (C 4 H 4 6 ) 2 (Fe 2 2 )K 2 ; they are prepared 
by dissolving recently precipitated ferric hydrate in hot solutions of the 
hydro-alkaline tartrate. They only react with ferro- and sulphocyanides 
after addition of a mineral acid. 

Ferric Ferrocyanide — Ferri f err ocyanidum (U. S.) — Prussian blue 
— (FeC 6 N 6 ) 3 (Fe 2 ) 2 + 18Aq. — a dark blue precipitate formed when potas- 
sium ferrocyanide is added to a ferric salt. It is insoluble in water, alco- 
hol, ether, and dilute acids ; soluble in oxalic acid (blue ink); alkalies 
turn it brown. 



ALUMINIUM. 



381 



Ferrous Ferricyanide — TurnbulVs blue — (Fe 2 C ls N ) Fe 3 + n Aq. — a 
dark blue precipitate, produced by potassium ferricyanide with ferrous 
salts. 

Analytical Characters. — Ferrous salts are acid, colorless when 
anhydrous, pale green when hydrated ; oxidized by air to basic ferric 
compounds. Potash, greenish white precipitate, insoluble in excess, 
changing to brown in air. Ammonium hydrate, greenish precipitate, 
soluble in excess, not formed in presence of ammoniacal salts. Ammo- 
nium sulphydrate, black precipitate, soluble in acids. Potassium fer- 
rocyanide, white precipitate, turning blue in air. Potassium ferricy- 
anide, blue precipitate, soluble in potash, insoluble in hydrochloric acid. 

Ferric salts are acid, and yellow or brown. Potash or ammonium 
hydrate, voluminous, red-brown precipitate. Hydrogen sulphide in acid 
solution, milky deposit of sulphur, ferric reduced to ferrous compound. 
Ammonium sulphydrate, black precipitate. Potassium ferrocyanide, 
dark blue precipitate, insoluble in hydrochloric acid, soluble in potash. 
Potassium sidphocyanate, dark red color ; prevented by tartaric and 
citric acids. Tannin, blue-black color. 



III. ALUMINIUM GROUP. 



Glucinium Gl , 

Aluminium Al , 



13.8 

27.5 



Gallium Ga 69.9 

Indium In 113.4 



This group is placed in the third class by virtue of the existence of 
the aluminates, and of the relations between the compounds of these ele- 
ments and some of those of the previous groups. They form, however, 
but one series of compounds, corresponding to the ferric, containing the 
group (M 2 ) V1 . No acids or salts of the members of the group, other than 
aluminium, are known; yet their resemblances in other points are such as 
to forbid their separation. 



ALUMINIUM. 



Al 



27.5 



This, the only element of the group of practical importance, although 
very abundant in combination, was only isolated in 1817 by Woehler, by 
a method which has since become general for the separation of metals 
whose compounds are difficultly reducible, which consists in passing the 
vapor of the chloride over sodium heated to redness. 

Aluminium is a bluish white metal ; hard, very malleable and ductile 
when annealed from time to time ; slightly magnetic ; a good conductor 
of electricity ; fuses at about 700°; non-volatile ; sp. gr. 2.56 when cast, 
2,67 when rolled. It is not affected by air or oxygen, except at very 
high temperatures, and even then very superficially. If, however, it 
contain silicon, it burns readily, forming aluminium silicate. Boron, 
silicon, and the elements of the chlorine group combine with it directly. 
It does not decompose water at a red heat. Hydrochloric acid, gaseous 
or in solution, attacks it, hydrogen is given off, and aluminium chloride 
formed. It dissolves readily in alkaline solutions with liberation of hy- 
drogen and formation of aluminates. It unites with copper to form a 



382 GENERAL MEDICAL CHEMISTRY. 

golden yellow alloy, known as aluminium bronze. The great toughness 
and lightness of aluminium and of its alloys render it valuable for the 
manufacture of metallic objects where lightness is desirable. 

Aluminium oxide — Alumina — A1 2 3 — exists in nature, nearly pure, 
in corundum, emery, ruby, sapphire, and topaz. It is obtained artificially 
by calcining the hydrate, and is also formed when ammonia alum (q. v.) is 
calcined at a red heat. It is a light, white, odorless, tasteless powder, fuses 
with difficulty, and, on cooling, forms crystals which are hard enough to 
scratch glass. Unless it have been heated beyond dull redness, it combines 
with water, the union being attended with liberation of heat. It is at- 
tacked with great difficulty by acids, its best solvent being sulphuric 
acid diluted with its weight of water. It also dissolves with difficulty in 
alkaline solutions, but combines with fused potash and soda to form alumi- 
nates. It is not reduced by charcoal. 

Aluminium hydrate, A1 2 H 6 6 — is formed when a solution of an 
aluminium salt is precipitated by ammonium hydrate or carbonate. It 
forms a gelatinous precipitate which, when washed and dried, leaves an 
amorphous, translucid mass. When it is formed in the presence of color- 
ing matters, these are mechanically carried down with it, and the dried 
deposits are used as pigments, known as lacs y it is insoluble in water 
when freshly precipitated; soluble in acids and solutions of the fixed 
alkalies. With the acids it forms salts of aluminium; and with the 
alkalies, aluminates of the alkaline element. When heated to near red- 
ness it is decomposed into aluminium oxide and water. A soluble variety 
of alumina has been obtained by dialysing a solution of alumina in alu- 
minium chloride solution, or by heating for 240 hours a dilute solution of 
aluminium acetate. 

Aluminates are for the most part crystalline, soluble compounds, 
obtained by the action of metallic oxides or hydrates upon alumina. JPotas- 
sium aluminate, Al 2 4 K 2 -)-3Aq. — is formed by dissolving recently pre- 
cipitated aluminium hydrate in potash solution. It forms white crystals; 
very soluble in water, insoluble in alcohol; caustic and alkaline. By a 
large quantity of water it is decomposed into aluminium hydrate and a 
more alkaline salt, A1 4 9 K 6 . Sodium aluminate. — The aluminate Al 2 
4 Na 2 is not known. That having the composition Al 4 9 Na 6 is prepared 
industrially, for use in dyeing, by heating to redness a mixture of one 
part of sodium carbonate and two parts of a native, ferruginous alumin- 
ium hydrate (beauxite), It is insoluble in water, and is decomposed by 
carbonic acid with precipitation of aluminium hydrate. 

Aluminium chloride, A1 2 C1 6 — is prepared industrially as a step in 
the manufacture of aluminium. It crystallizes in colorless, hexagonal 
prisms; fusible; volatile; deliquescent; very soluble in water and in 
alcohol. From a hot, concentrated solution it separates in prisms con- 
taining 12 Aq. It absorbs hydrogen sulphide, hydrogen phosphide, and 
ammonia, with which it forms compounds. 

An impure solution of aluminium chloride is used as a disinfectant 
under the name chloralum. 

Salts. — Aluminium Sulphates, (S0 4 ) 3 Al 2 + 18Aq. — is prepared arti- 
ficially on a large scale from kaolin. It is also formed (Aluminii sulphas, 
U. S.) by dissolving aluminium hydrate in moderately diluted sulphuric 
acid. 

It crystallizes with difficulty in thin, flexible plates; soluble in water, 
very sparingly soluble in alcohol. When heated, it fuses in its water of 
crystallization, which it gradually loses up to 200°, when a white, amor- 



ALUMINIUM. 383 

phous powder of the anhydrous salt, (S0 4 ) 3 A1 2 , remains; this at a red 
heat is decomposed, leaving- a residue of pure alumina. 

Alums are double sulphates of the alkaline metals, and the higher 
sulphates of the elements of this and the preceding group. When crys- 
tallized, they contain 24 Aq., and have the general formula: (S0 4 ) 3 (M 2 ) V1 , 
S0 4 R' 2 + 24Aq., in which (M 2 ) may be (Fe 2 ), (Mn,), (Cr,), (Al 2 ), or (Ga 2 ); 
and R 2 may be K 2 , Na 2 , Rb 2 , Cs 2 , Tl 2 , or (NH 4 ) 2 . They are isomorphous. 

The substance formerly known as alum is the double sulphate of alu- 
minium and potassium, (S0 4 ) 3 Al 2 , S0 4 K 2 -{-24Aq. It is manufactured 
from aluminous schists, from clays free from iron, and from ahiminite, a 
native subsulphate of aluminium and potassium. That from the last- 
named source crystallizes in cubes, and is known as cubic or Roman alum. 
It is formed when concentrated solutions of sulphates of aluminium and 
of potassium are mixed in suitable proportions. 

It crystallizes in large, transparent, regular octahedra; has a sweet- 
ish, astringent taste; 100 parts of water at 10° dissolve 9.52 parts of 
alum; and at 100°, 357.48 parts. When heated to about 92°, it fuses in 
its water of crystallization, and gradually loses 45.5 per cent, of its 
weight of water as it is heated to a temperature near redness. The pro- 
duct, wmich is readily pulverizable, and slowly but completely soluble in 
20 — 30 times its weight of water, is known as burnt alum, and is the an- 
hydrous double sulphate. At a bright red heat, sulphur dioxide and 
oxygen are given off, and alumina and potassium sulphate remain. At a 
higher temperature, potassium aluminate is formed. Its solutions, acid 
in reaction, deposit aluminium hydrate when neutralized with ammonium 
hydrate. 

Potash alum is giving place in the arts to the cheaper aluminium and 
ammonium sulphate, or ammonia alum, (S0 4 ) 3 A1 2 , S0 4 (NH 4 ) 2 + 24Aq., 
which differs from potash alum in being more soluble between 20° and 
30°, and less soluble in colder or warmer water, and in the manner in 
which it is affected by heat. It fuses in its water of crystallization, as 
does potash alum; at about 205°, the temperature reached in making 
burnt alum, it loses its ammonium sulphate, leaving a white, hygroscopic 
substance, very slowly and incompletely soluble in water; when more 
strongly heated, it leaves alumina. 

Alum and the alkaline bicarbonates decompose each other with for- 
mation of aluminium hydrate, an alkaline sulphate, and carbon dioxide, a 
reaction utilized in alum baking-powders [q. v.). 

Silicates are very abundant in the different varieties of clay, feld- 
spar, albite, labradorite, mica, etc. The clays are hydrated aluminium 
silicates, more or less contaminated with alkaline and earthy salts and 
iron, to which last certain clays owe their color. The purest is kaolin, 
or porcelain clay, a white or grayish powder. They are largely used in 
the manufacture of the different varieties of bricks, terra cotta, pottery, 
and porcelain. Porcelain is made from the purer clays, mixed with sand 
and feldspar; the former to prevent shrinkage, the latter to bring the 
mixture into partial fusion, and to render the product translucent. The 
fashioned articles are subjected to a first baking; the porous, baked clay 
is then coated with a glaze, usually composed of oxide of lead, sand, 
and salt. Durinsr a second bakinir, the gflaze fuses and coats the article 
with a hard, impermeable layer. The coarser articles of pottery are 
glazed by throwing sodium chloride into the fire; the salt is volatilized, 
and, on contact with the hot aluminium silicate, deposits a coating of the 
fusible sodium silicate, which hardens on cooling. 



384 GENERAL MEDICAL CHEMISTRY. 

Aluminium Acetate, (C 2 H 3 2 ) 6 (A1 2 ) — is obtained only in solution, 
by decomposing a concentrated solution of aluminium sulphate with lead 
acetate, or by dissolving aluminium hydrate in acetic acid. Jt is an un- 
crystallizable liquid, having a styptic taste, which is decomposed when 
heated or on standing, with formation of basic acetates. Is extensively 
used in dyeing. 

Analytical Characters. — Potash or soda, white precipitate, soluble 
in excess; Ammonium hydrate, white precipitate, almost insoluble in 
excess, especially in the presence of ammoniacal salts; Sodium phosphate, 
white precipitate, readily soluble in potash and soda, but not in ammo- 
nium hydrate ; readily soluble in mineral acids, but not in acetic acid; 
Blowpipe; on charcoal does not fuse, and, when moistened with solution 
of cobalt nitrate, turns dark sky-blue. 



V. LEAD GROUP. 
LEAD Pb 207 

This element is usually classed with cadmium, bismuth, or copper 
and mercury; it differs, however, from bismuth in being divalent or 
quadrivalent, but not trivalent, and in forming no compounds resembling 
those of bismuthyl (BiO); from cadmium in the nature of its oxygen 
compounds; and from mercury and copper in forming no compounds 
similar to the mercurous and cuprous salts. Indeed, the nature of the 
lead compounds is such that the element is best classed in a group by it- 
self, which finds a place in this class by virtue of the existence of potas- 
sium plumbate. 

The most abundant ore of lead is a sulphide known as galena, which 
is worked for lead and silver. The ore is roasted; the mixture of oxide, 
sulphide and sulphate so formed is heated in a reverberatory furnace, 
to yield an impure metal, called ivork-lead. If the ore be rich in silver, 
it is subjected to refining by crystallization and cupellation. At first, 
the work-lead is fused and allowed to cool slowly; crystals of lead sepa- 
rate and are removed, while the silver remains in the more fusible alloy. 
After several crystallizations, the concentrated alloy is fused in the cu- 
pelling furnace and a powerful current of air is driven over the surface of 
the molten metal; the lead is thus oxidized and is driven off by the cur- 
rent of air through a notch, whose depth is increased as the operation 
proceeds. As the last film of lead oxide is carried off, the clear surface of 
the fused silver is exposed and the mass brightens, indicating the termina- 
tion of the operation. 

Lead is a grayish white metal; brilliant upon freshly cut surfaces, 
very soft and pliable, not very malleable or ductile, fuses at 334°, and, 
on cooling, crystallizes in octahedra; a poor conductor of electricity; a 
better conductor of heat. When expanded by heat, it does not, on cool- 
ing, return to its original volume. 

Lead, when exposed to air, is oxidized; it is not acted on by pure 
water, deprived of air; by the combined action of air and water, lead is 
oxidized to the hydrate, PbH 2 2 , which dissolves to an appreciable ex- 
tent. The solvent action of water upon lead is increased, owing to the 
formation of basic salts, by the presence of nitrogenized organic matters, 
nitrates, and nitrites; on the other hand, carbonates, sulphates, and car- 
bon dioxide, by their tendency to form insoluble coatings, diminish the 



LEAD. 385 

solubility of the metal in water. Nitric acid dissolves lead readily ; sul- 
phuric acid, when cold, does not affect it; but when heated, dissolves it 
the more readily the more concentrated the acid. Hydrochloric acid of 
sp. gr. 1.12 attacks it, especially if heated. 

Several alloys of lead are used in the arts: Type-metal = lead and anti- 
mony; pewter=lead and tin; plumber's solder=lead and tin. 

Oxides.— Lead forms five oxides: Pb 2 0, PbO, Pb 3 4 , Pb 2 3 , and Pb0 2 . 

Lead Monoxide — Protoxide — Massicot — Litharge — Plumbi oxidum 
(U. S., Br.)P — bO is prepared by calcining lead or its carbonate or nitrate. 
If the product have been fused, it is litharge/ if not, massicot/ the two 
varieties differing in color and in texture, but not in composition. Mas- 
sicot is prepared by calcining lead and removing the pellicle as soon as it 
is formed; litharge, by fusing massicot, and allowing it to cool. When 
fused, it crystallizes in mica-like plates; from its solution in soda or 
potash, it is deposited in white, rhombic dodecahedra or in rose-colored 
cubes. It fuses at a heat approaching redness; it volatilizes at a white 
heat; sp. gr. 9.277; after fusion, 9.5. It is sparingly soluble in water, 
the solution being; alkaline in reaction. 

When heated to 300° in contact with air, it is oxidized to minium. 
When fused in earthen crucibles it forms a fusible silicate, and thus per- 
forates the vessel. It is readily reduced by charcoal or hydrogen. 
Chlorine converts it into the chloride with separation of oxygen. It is a 
powerful base; it decomposes the alkaline salts with liberation of the 
alkali; it dissolves readily in nitric acid and in hot acetic acid, with form- 
ation of nitrate or acetate. When rubbed up with oils it decomposes 
the glyceric ethers, and combines with the fatty acids to form lead-soaps; 
one of which, the oleate, is the emplastrum plumbi (U. S., Br.). It also 
combines with the alkalies and earths to form plumbites. Calcium 
plumbite, Pb 2 3 Ca, is a crystalline compound, formed by heating litharge 
with milk of lime. Its solution is used as a hair-dye. 

Plumboso-pltjmbic Oxide — Red oxide of lead — Minium — Red lead — 
Pb 3 4 or Pb0 2 , 2PbO or Pb0 3 Pb + PbO — is prepared for use as a pig- 
ment, and in the manufacture of glass, by heating litharge to 300° in 
contact with air. It ordinarily has the composition given above, and has 
been considered as composed of one molecule of the dioxide combined 
with two of the monoxide; or as the lead salt of plumbic acid combined 
with a molecule of the monoxide. An orange-colored variety is formed 
by heating lead carbonate to 300°. 

It is a brilliant red powder, sp. gr. 8.62. When strongly heated it 
is converted into litharge; a change which is also brought about by redu- 
cing agents. Nitric acid changes its color to brown, dissolving the mon- 
oxide and leaving the dioxide. Hydrochloric acid decomposes it with 
formation of chlorine, lead chloride, and water. 

The commercial product is frequently contaminated with oxide of 
iron and brick-dust. It should dissolve in dilute nitric acid to which a 
fragment of sugar has been added. 

Lead Dioxide — Peroxide of lead — Puce oxide of lead — Rinoxide of 
lead — Plumbic anhydride — Pb0 2 — is prepared either by dissolving the 
monoxide out of minium by dilute nitric acid, or by passing a current 
of chlorine through water holding lead carbonate in suspension. 

It is a dark, reddish brown powder, sometimes crystalline; sp. gr. 
8.903 to 9.190; insoluble in water. When heated it loses half its oxygen 
and is converted into the monoxide. It is a valuable oxidizing agent. 
It absorbs sulphur dioxide to form lead sulphate. 



386 GENERAL MEDICAL CHEMISTRY. 

Plumbic Acid, Pb0 3 H 2 — is formed in crystalline plates, at the positive 
pole, when alkaline solutions of the lead salts are decomposed by a weak 
current. 

The alkalies dissolve lead dioxide to form well-defined but unstable 
salts, called plurnbates. Potassium plumbate, Pb0 3 K 2 -f 3Aq., is obtained 
in cubic crystals when lead dioxide is gently heated in a silver vessel with 
concentrated potash solution. It is decomposed by water. 

Lead Sulphide, PbS — exists in nature in cubic crystals as the chief 
ore of lead, galena. It is also formed by direct union of the elements; by 
heating lead monoxide with sulphur or vapor of carbon disulphide; or by 
decomposing a solution of a lead salt with hydrogen sulphide or an alka- 
line sulphydrate. 

The native sulphide is bluish gray and has a metallic lustre; sp. gr. 
7.58; that obtained by precipitation is a black powder of sp. gr. 6.92-4. 
It fuses at a red heat and is partially sublimed, partially converted into 
a subsulphate with loss of sulphur. When heated in air it is converted 
into sulphate and oxide, and sulphur dioxide. Heated in hydrogen it is 
reduced. Hot nitric acid oxidizes it to the sulphate; hot hydrochloric 
acid converts it into the chloride; boiling sulphuric acid converts it into 
the sulphate and disengages sulphur dioxide. 

Chlorides. — Two compounds of chlorine and lead are known, PbCl. 
and PbCL. 

Lead Chloride, PbCl„ — is formed by the action of chlorine upon 
lead at a red heat by the action of boiling hydrochloric acid upon the 
metal; and by double decomposition between a soluble salt of lead and a 
chloride. In the last case, if the solutions be cold and not too dilute, the 
chloride is precipitated. 

It crystallizes in plates or in silky, hexagonal needles; soluble in loo 
parts of water at 12.5°; less soluble in water containing hydrochloric acid; 
more soluble in concentrated hydrochloric acid and in boiling water. 

Lead also forms several oxychlorides; that having the composition 
PbCl 2 ,7PbO is used as a pigment, and is known as Cassel, Paris, Verona, 
or Turner's yellow. 

Iodide — Plumbi iodidum(XJ. S., Br.) — Pbl 2 — is deposited as a bright 
yellow powder when a solution of potassium iodide is added to a solu- 
tion of a lead salt. It is almost insoluble in cold water, sparingly soluble 
in boiling water. When fused in air it loses iodine and is converted 
into an oxysalt. When exposed to light and moisture it is decomposed 
with liberation of iodine. It dissolves in solutions of ammonium chlo- 
ride, sodium hyposulphite, alkaline iodides, and potassium hydrate. 

Salts. — Nitrates. — Besides a neutral salt, lead forms basic nitrates, 
some of which seem to indicate the existence of nitrogen acids similar to 
those of phosphorus. 

(N0 4 ) 2 Pb 3 , Lead orthonitrate (P0 4 ) 2 Pb 3 , Lead orthophosphate. 

N 2 T Pb 2 , Lead pyronitrate P 2 7 Pb 2 , Lead pyrophosphate. 

(N0 3 ) 2 Pb, Lead metanitrate (P0 3 ) 2 Pb, Lead metaphosphate. 

Neutral lead nitrate — Plumbi nitras (U. S., Br.) — (N0 3 ) 2 Pb — is formed 
by solution of lead or its oxides in excess of nitric acid. It forms anhyd- 
rous crystals, soluble in 1.98 parts water at 17.5°, and in 0.7 parts at 100°. 
It is decomposed by heat, with liberation of nitrogen tetroxide. 

Sulphates. — The ?ieutral sulphate, S0 4 Pb — is formed by the action 
of hot concentrated sulphuric acid on lead; or, by double decomposition 



LEAD. 387 

between a sulphate and a lead salt in solution. It is a white powder, 
almost insoluble in water; soluble in concentrated sulphuric acid, from 
which it is deposited on dilution. 

Chromates. — The neutral chromate, Cr0 4 Pb — is formed by precipi- 
tating lead nitrate with potassium chromate, and is used as a pigment, 
chrome yellow. It is insoluble in water; soluble in alkalies. 

Acetates. — The Neutral acetate — Salt of Saturn — Sugar of lead — 
Plumbi acetas — (C 2 H 3 2 ) 2 Pb + 3Aq. — is prepared by dissolving litharge in 
acetic acid; or, by exposing lead in contact with acetic acid to the at- 
mosphere, evaporating and crystallizing. 

It crystallizes in large, oblique, rhombic prisms, sweetish, with a me- 
tallic after-taste; soluble in 1.5 parts cold water and in 8 parts alcohol. 
The solutions are acid. By exposure to the air it effloresces upon the 
surface and is superficially converted into carbonate. It fuses at 75.5°; 
loses Aq. and a part of its acid to 100°, forming the sesquibasic acetate. 
At 280° it enters into true fusion, and at a slightly higher temperature is 
decomposed into carbon dioxide, acetone, and lead. Its aqueous solution 
dissolves litharge, with formation of basic acetates. 

Of the subacetates, that having the composition (C 2 H 3 2 )PbOH, 2PbO, 
the sexbasic acetate, is the only one requiring mention. It is the main 
constituent of Liq. plumbi subacetatis (U. S., Br.), or GoularcVs extract, 
obtained by boiling a solution of the neutral acetate with lead monoxide 
in fine powder. This solution becomes milky when added to ordinary 
water, by formation of lead sulphate and carbonate. 

Lead Carbonate — Plumbi carbonas (U. S., Br.) — C0 3 Pb — is formed 
by double decomposition between a carbonate and a salt of lead in solu- 
tion, or by passing carbon dioxide through a solution containing lead. 
It is a white powder, sp. gr. 6.43; insoluble in water. 

Besides the neutral salt there exist several basic carbonates which occur 
in varying proportions in the commercial product known as ceruse or 
white lead. This is prepared by several processes. In the Clichy process, 
which is that usually adopted, litharge is dissolved in lead acetate so- 
lution, and the subacetate thus produced is decomposed by a current of 
carbon dioxide, the neutral acetate being regenerated and used again. 

White lead is used in oil-painting, forming apart of all but the darkest 
pigments. The darkening of lead whites by exposure to air is due to the 
presence of traces of hydrogen sulphide in the atmosphere. The regen- 
eration of oil-paintings dimmed by atmospheric action is accomplished by 
oxygenated water, which oxidizes the dark sulphide to the white sulphate. 

Analytical characters. — Hydrogen sulphide in acid solution'; a 
black precipitate, insoluble in acids and in alkaline sulphides. Am- 
monium sulphydrate ; black precipitate, insoluble in excess. Hydro- 
chloric acid ; white precipitate, soluble in boiling water, from which it 
crystallizes on cooling; not altered in appearance by ammonium hydrate. 
This reaction does not occur in dilute solutions. Ammonium hydrate / 
white precipitate, insoluble in excess. Potassium hydrate ; white pre- 
cipitate, soluble in excess, especially when heated. Sulphuric acid or 
sulphate / white precipitate, insoluble in weak acids, soluble in solution 
of ammonium tartrate. Potassium iodide ; yellow precipitate, sparingly 
soluble in boilino; water, soluble in a larg-e excess of the reagent. Potas- 
slum chromate ; yellow precipitate, soluble in potash solution. Iron, or 
zinc separate the element from solutions of its salts. 

Action on the economy. — All of the soluble compounds of lead 
and those which, although not soluble, are readily convertible into solu- 



388 GENERAL MEDICAL CHEMISTRY. 

ble compounds by water, air, or the digestive fluids, are actively poisonous. 
Some are also injurious by their local action upon the tissues with which they 
come in contact; such are the acetate, and, in a less degree, the nitrate. 

The chronic form of lead intoxication, painter's colic, etc., is purely 
poisonous, and is produced by the continued absorption of minute quan- 
tities of lead, either by the skin, lungs, or stomach. The acute form pre- 
sents symptoms referable to the local as well as to the poisonous action 
of the lead salt, and is usually caused by the ingestion of a single dose of 
the acetate or carbonate. 

Metallic lead, although probably not poisonous of itself, causes chronic 
lead-poisoning* by the readiness with which it is converted into com- 
pounds capable of absorption. The sources of poisoning by metallic lead 
are: the contamination of drinking water which has been in contact with 
the metal (see p. 56); the use of articles of food or of chewing tobacco 
which has been packed in tin-foil containing an excess of lead; the 
drinking- of beer or other beverages which have been in contact with 
pewter; or the handling of the metal and its alloys. 

Almost all the compounds of lead may produce painter's colic. The 
carbonate, in painters, artists, manufacturers of white lead, and in per- 
sons sleeping in newly painted rooms; the oxides, in the manufacturers of 
glass, pottery, sealing-wax, and litharge, and by the use of lead-glazed 
pottery; by other compounds, by the inhalation of the dust of cloth fac- 
tories, and by the use of lead hair-dyes. 

Acute lead-poisoning is by no means of as common occurrence as the 
chronic form, and usually terminates in recovery. It is caused by the 
ingestion of a single large dose of the acetate, subacetate, carbonate, 
or of red lead. In such cases the administration of magnesium sulphate 
is indicated; it enters into double decomposition with the lead salt to 
form the insoluble lead sulphate. 

Lead once absorbed is eliminated very slowly, it becoming fixed by 
combination with the albuminoids, a form of combination which is ren- 
dered soluble by potassium iodide. The channels of elimination are by 
the perspiration, urine, and bile. 

In the analysis for mineral poisons (see p. 128), the major part of 
the lead is precipitated as sulphide in the treatment by sulphuretted 
hydrogen. The lead sulphide remains upon the filter after extraction 
with ammonium sulphydrate; it is treated with warm hydrochloric acid, 
which decolorizes it by transforming the sulphide to chloride. The lead 
chloride thus formed is dissolved in hot water, from which it crystallizes 
on cooling. The solution still contains lead chloride in sufficient quantity 
to respond to the tests for the metal. 

Although lead is not a normal constituent of the body, the every-day 
methods in which it may be introduced into the economy, and the slow- 
ness of its elimination are such as to render the greatest caution neces- 
sary in drawing conclusions from the detection of lead in the body after 
death. 

VI. BISMUTH GROUP. 

BISMUTH Bi .210 

This element is usually classed along with antimony: by the older 
authors among the metals, and by the more modern in the phosphorus 
group of metalloids. We are led, however, to rank bismuth in our third. 



BISMUTH. 389 

class and in a group alone, because: 1st, while the so-called salts of an- 
timony are not salts of the element, but of the radical antimonyl (SbO)', 
bismuth enters into saline combination, not only in the radical bismuthyl, 
/BiO)', but also as an element, as in the nitrate (N0 3 ) 3 Bi; 2d, while 
the compounds of the elements of the nitrogen group in which those 
elements are quinquivalent, are, as a rule, more stable than those in 
which they are trivalent, only one compound of bismuth is known in 
which that element is quinquivalent, and that one is a very unstable 
acid; 3d, the hydrates of the nitrogen group are strongly acid and their 
corresponding salts are stable and well-defined; but those hydrates of bis- 
muth which are acid are but feebly so, and the bismuthates are formed 
with difficulty and are unstable; 4th, no hydrogen compound of bismuth 
is known. 

Bismuth crystallizes in rhombohedra; has a brilliant, metallic lustre, 
with bluish and reddish reflections; is hard and brittle; fuses at 247°; sp. 
gr. 9.935 when crystallized, 9.677 when annealed. 

It is only superficially oxidized in cold air; heated to redness in air, 
it becomes coated with a yellow film of oxide. Pure water does not act 
on it, except at a white heat; in water containing carbonic acid it forms 
a crystalline subcarbonate. Chlorine, bromine, and iodine combine with it 
directly. Hot sulphuric acid dissolves it as sulphate. Nitric acid dis- 
solves it as nitrate. 

It is usually contaminated with arsenic, from which it is best puri- 
fied by heating to redness a mixture of powdered bismuth, potassium 
carbonate, soap, and charcoal, under a layer of charcoal. After an hour 
the mass is cooled; the button is separated and fused until its surface be- 
gins to be coated with a yellowish brown oxide. 

Oxides. — Four oxides are known: Bi 2 2 , Bi 2 3 , Bi 2 4 , Bi 2 5 . 

Bismuth Trioxide — Protoxide — JBismiithi oxidum (Br.) — Bi 2 3 — is 
formed by decomposing a bismuth or bismuthyl salt by an alkali, and 
boiling the liquid on the precipitate. It is a pale yellow, insoluble pow- 
der; sp. gr. 8.2; fuses at a red heat. It is reduced by hydrogen or char- 
coal. It dissolves in hydrochloric and nitric acids, and in fused potash. 

Hydrates. — Bismuth forms at least four hydrates: JBismuthous hy- 
drate, Bi"'H 3 3 , is formed as a white precipitate when potash or ammonia 
is added to a cold solution of a bismuth salt. This hydrate, when dried, 
loses water and forms bismuthyl hydrate (BiO) 'HO. JBismuthic acid, 
(Bi0 2 )' HO, is deposited as a red powder when chlorine is passed through 
a boiling solution of potash holding bismuthous hydrate in suspension. 
JPyrobismuthic acid, Bi 2 7 H 4 , is a dark brown powder, precipitated from 
solutions of bismuth nitrate by potassium cyanide. 

Salts of bismuth. — Nitrate, (N0 3 ) 3 Bi — obtained by dissolving bis- 
muth in nitric acid and crystallizing. It crystallizes with 5 Aq. in large, 
colorless prisms; at 150°, or on contact with water, it is converted into 
bismuthyl nitrate; at 260°, into the trioxide. 

Salts of bismuthyl. — They contain the group (BiO)', and are 
formed from the corresponding: bismuth salt by the action of water. 

Nitrate — Subnitrate or Magistery of bismuth — Bismuthi subnitras 
(U. S., Br.) — N0 3 (BiO) — is formed by decomposing a solution of bismuth 
nitrate with a large quantity of water. In its preparation for use in 
medicine, measures must be taken to separate arsenic; in the Br. P. 
process, the bismuth itself is purified; in the U. S. P. method, bismuth 
nitrate is decomposed by sodium carbonate; the bismuthyl nitrate so 
formed is washed, redissolved in nitric acid, the solution slowly precipi- 



390 GENERAL MEDICAL CHEMISTRY. 

tated with ammonium hydrate, and the product washed. In the latter 
process it is expected that the arsenic will be washed out as sodium 
arsenate, an end seldom attained in practice. 

It is a heavy, white powder, faintly acid; when recently precipitated, 
water dissolves it in small quantity, but deposits it again on standing. 
It is decomposed by pure water, but not by water containing -^_ ammo- 
nium nitrate. It usually contains 1 Aq., which it loses at 100°. 

The cosmetic known as pearl white is sometimes this salt, sometimes 
bismuthyl chloride. 

Carbonate — Bismuthi subcarbonas (U. S.) — JBismuthi carbonas (Br.) 
— C0 3 (BiO) 2 — a white precipitate, formed by alkaline carbonates in solu- 
tions of bismuth nitrate. Heat decomposes it into carbon dioxide and 
bismuth trioxide. 

Analytical characters. — Water, white precipitate, even in the 
presence of tartaric acid, but not in presence of nitric, hydrochloric, or 
sulphuric acid. Hydrogen sulphide, black precipitate, insoluble in dilute 
acids and in alkaline sulphides. Ammonium sulphydrate, black precipi- 
tate, insoluble in excess. Potash, soda, or ammonium hydrate, white pre- 
cipitate, insoluble in excess and in tartaric acid, turns yellow when the 
liquid is boiled. Potassium ferrocyanide, white precipitate, insoluble in 
hydrochloric acid. Potassium ferricyanide, yellowish precipitate, soluble 
in hydrochloric acid. Infusion of galls, orange precipitate. Potassium 
iodide, brown precipitate, soluble in excess. 

Action on the economy. — Although the medicinal compounds of 
bismuth probably are poisonous, if taken in sufficient quantity, the ill 
effects ascribed to them are in most, if not all cases, referable to contami- 
nation with arsenic. Symptoms of arsenical poisoning have not only been 
frequently observed when the subnitrate has been taken internally, but 
also when it has been used as a cosmetic. 

When preparations of bismuth are administered, the alvine discharges 
contain bismuth sulphide as a dark brown powder. 



VII. TIN GROUP. 

Titanium, Ti., 50 ; Tin, Sn., 118 ; Zirconium, Zr., 89.6. 

Titanium and tin are divalent in one series of compounds, SnCl 2 , and 
quadrivalent in another, SnCl 4 . Zirconium, so far as known, is always 
quadrivalent. Each of these elements forms an acid (or salts correspond- 
ing to one) of the composition MO a H 2 , and a series of oxysalts of the 
composition (N0 3 ) 4 M ir . 

TIN. 
Stannum Sn 118 

The only member of this gr©up of practical interest, is obtained chiefly 
from a native stannic oxide, cassiterite or tinstone. 

When required pure, commercial tin is dissolved in hydrochloric acid, 
the solution filtered and evaporated; the chloride dissolved in water and 
decomposed with ammonium carbonate; the protoxide reduced by char- 
coal. 



TIN. 391 

Tin is a bluish white metal, soft, malleable, ductile; sp. gr. 7.285 
when cast, 7.293 when hammered; fuses at 228°; emits a peculiar sound, 
the tin cry, when bent. 

Air affects it but little at ordinary temperatures; when heated in air 
it is oxidized; more rapidly if alloyed with lead. It oxidizes slowly in 
water, more rapidly in salt water; if alloyed with lead, that metal is more 
readily dissolved by water than when it is pure. Hydrochloric acid dis- 
solves it as stannous chloride. Nitric acid, in presence of a small quan- 
tity of water, converts it into metastannic acid. Alkaline solutions dis- 
solve it as metastannates. Chlorine, bromine, iodine, sulphur, phos- 
phorus, and arsenic combine with it directly. 

It is used in the arts principally to protect iron or copper surfaces 
from atmospheric influences. Tin plates are thin sheets of iron coated 
with tin. Copper and iron vessels are tinned, after brightening, by con- 
tact with molten tin. The practice of using an alloy of lead and tin in 
tinning is to be avoided, as the lead, when thus alloyed, is readily dis- 
solved. Tin-foil, thin laminse of tin, is used to exclude air and moisture, 
and in the silvering of mirrors. Pewter, bronze, bell metal, speculum 
metal, gun metal, britannia metal, solder and Rose's alloy, contain tin. 
The compounds of tin are largely used in dyeing. 

Oxides. — Two oxides are known, SnO and SnO„. 

Stannic Oxide — Binoxide of tin — Sn0 2 — exists in nature as cassite- 
rite, and is formed when tin or stannous oxide is calcined in air. Under 
the name putty powder it is used as a polishing material. 

Hydrates. — Stannous hydrate, SnH 2 2 — is a white precipitate pro- 
duced by alkaline hydrates and carbonates in a solution of stannous 
chloride. Stannic acid, Sn0 3 H,„ is formed by the action of the same re- 
agents on stannic chloride. Metastannic acid, Sn 5 O n H 2 , is a white, in- 
soluble powder, formed by acting on tin with concentrated nitric acid. 

Chlorides. — Two chlorides of tin are known: 

Stannous Chloride — Protochloride of tin — Tin crystals — SnCl 2 — 
is obtained by dissolving tin in hydrochloric acid. It crystallizes with 
2 Aq. in colorless prisms, soluble in a small quantity of water, but decom- 
posed, with formation of an oxychloride, by a large quantity, unless hy- 
drochloric acid be added. In air it is converted into stannic chloride and 
oxychloride. Oxidizing and chlorinating agents convert it into stannic 
chloride. It is a useful reducing agent, separates gold from its chloride, 
and converts mercuric chloride into mercurous chloride and mercury. It 
is used as a mordant in dyeing. 

Stannic Chloride — Bichloride of tin — Liquid of Libavius — SnCl 4 
— is formed from the preceding compound, or by the action of dry chlo- 
rine on tin, as a fuming, yellowish liquid; sp. gr. 2.28; boils at 120°. 

Salts. — Stannous Nitrate, (N0 3 ) 2 Sn — formed when stannous hy- 
drate is dissolved in nitric acid. The solution deposits metastannic acid. 

Stannic Nitrate, (N0 3 ) 4 Sn — formed when stannic oxide is dissolved 
in nitric acid. 

Stannous Sulphate, S0 4 Sn, and Stannic Sulphate, (S0 4 ) 2 Sn — 
are produced, the former when stannous hydrate is dissolved in hot dilute 
sulphuric acid, and the latter when tin is dissolved in strong boiling 
sulphuric acid. 

Analytical characters. — Stannous. — Potash or Soda, white pre- 
cipitate, soluble in excess; the solution deposits tin when boiled. Am- 
monium hydrate, white precipitate, insoluble in excess; turns olive-brown 
when the liquid is boiled. Hydrogen sulphide, dark brown precipitate, 



392 



GENERAL MEDICAL CHEMISTRY. 



soluble in potash, alkaline sulphides, and hot hydrochloric acid. Mercuric 
chloride, white precipitate, turning gray and black. Auric chloride, pur- 
ple or brown precipitate in presence of a small quantity of nitric acid. 
Zinc, deposit of tin. 

Stannic. — Potash or Ammonium hydrate, white precipitate, soluble 
in excess. Hydrogen sulphide, yellow precipitate, soluble in alkalies, 
alkaline sulphides, and hot hydrochloric acid. Sodium hyposxdphite, 
yellow precipitate, when heated. 



VIII. PLATINUM GROUP. 



Palladium, Pd., 106.5 ; Platinum, Pt., 198. 

IX. RHODIUM GROUP. 

Rhodium, Rh., 104 ; Ruthenium, Ru., 104 ; Iridium, Ir., 197.2. 

The elements of these two groups, together with osmium, are usually 
classed as " metals of the platinum ores." They all form hydrates (or 
salts representing them) having acid properties. Osmium has been re- 
moved because the relations existing between its compounds and those 
of molybdenum and tungsten are much closer than those which they ex- 
hibit to the compounds of these groups. The separation of the remaining 
platinum metals into two groups is based upon resemblances in the com- 
position of their compounds, as shown in the following table: 



Chlorides. 

PdCl 2 . ,PtCl 2 . . |RhCl 2 . . .RuCl 2 . .? 

PdCl 4 ..PtCl 4 .J ..RuCl 4 ..IrCl 4 .. 

.. . .lRh 2 Cl 6 . .Ru.Clc. .Ir 2 Cl G . . 



PdO . 


.PtO ... 


Pd0 2 '. 


'.Pt0 2 ... 


. 


• • • • 



Oxides. 

RhO ..RuO ..IrO 
Rh 2 3 ..Ru 2 3 ..Ir 2 0j 
Rh0 2 ..Ru0 2 ..Ir0 2 
Rh0 3 ..Ru0 3 ..Ir0 3 
..Ru0 4 .. 



PLATINUM. 



Pt 



198 



Exists in nature, associated with the other platinum metals, gold, 
lead, and iron; the ores containing 45 to 86 per cent, of platinum. 

It is a grayish white metal, sp. gr. 21.1 when cast, 21.5 when ham- 
mered; softens at a white heat; may be welded; fuses with difficulty; 
very malleable, ductile, and tenacious. When obtained by heating the 
double chloride of platinum and ammonium it forms a grayish mass, 
called spongy platinum. It is not oxidized by air or oxygen; combines 
directly with chlorine, phosphorus, arsenic, silicon, sulphur, and carbon. 
Aqua regia is the only acid which dissolves it. Platinum vessels are per- 
forated or deteriorated when heated with metals, easily reducible metallic 
oxides, mixtures capable of liberating chlorine, and phosphates, silicates, 
hydrates, nitrates, or carbonates of the alkaline metals. 

Platinic chloride, PtCl 4 — formed by dissolving platinum in aqua 
regia. It crystallizes in very soluble, yellow needles, whose solution is 
valuable as a test for ammonium and potassium. 



LITHIUM. 



393 



CLASS rv. 

Elements whose Oxides Unite with Water to form Bases; never 
to form Acids. Which form Oxysalts. 

I. SODIUM GROUP. 

Alkaline Metals. 

Rubidium Rb 85.4 

Caesium Cs 132.6 

Silver Ag 108. 

Each of the elements of this group forms a single chloride, M'Cl, and 
one or more oxides, the most stable of which has the composition M' 2 0; 
they are, therefor, univalent. Their hydrates, M'HO, are more or less 
alkaline and have markedly basic characters. Silver resembles the other 
members of the group in chemical properties, although it does not in 
physical characters. 





...Li 


.... 7 




. . . Na 


.... 23 




...K 


.... 39 



LITHIUM. 



Li 



A silver- white metal; tarnishes rapidly in air; is the lightest of the 
solid elements; sp. gr. 0.589; fuses at 180°; burns in air; decomposes 
water at the ordinary temperature. 

Oxide, Li 2 — is a white solid, formed by burning lithium in dry 
oxygen. It dissolves slowly in water with formation of the hydrate, 
LiHO. 

Chloride, LiCl — crystallizes in regular octahedra; very deliquescent; 
forms a double chloride with platinic chloride, which is soluble in water 
and in alcohol. 

Bromide — Liihii bromidum — LiBr — is formed by decomposing lith- 
ium sulphate with potassium bromide. Also by saturating a solution of 
hvdrobromic acid with lithium carbonate. It forms deliquescent nee- 
dles, which contain 91.95 percent, of bromine. 

Salts. — Carbonate — Lithii carbonas (U. S.) — C0 3 Li 2 — obtained by 
fusing lepidolite, a native silicate, with barium sulphate and carbonate 
and potassium sulphate; extracting with water, and precipitating with 
sodium carbonate. The product is purified by repeated washing with 
water, suspension in water through which carbon dioxide is passed, and 
reprecipitation by boiling the solution. It is soluble in water to the ex- 
tent of 1.2 parts per 100; 5.25 parts per 100 in water containing carbonic 
acid; insoluble in alcohol. With uric acid it forms lithium urate (q. v.). 

Analytical characters. — Ammonium carbonate, white precipitate 
in concentrated solutions, never in dilute solutions or in presence of large 
quantities of ammoniacal salts. Sodium j^osj^hates, white precipitate 



394 GENERAL MEDICAL CHEMISTRY. 

in neutral or alkaline solution, soluble in acids and in solutions of am- 
moniacal salts. It colors the Bunsen flame bright red, and has a spectrum 
of two bright lines— A= 6705 and 6102. 



SODIUM. 
Natrium Na 23.043 

Sodium is now obtained by a process based upon the reduction of the 
carbonate by coal. A mixture of dry sodium carbonate, coal, and chalk 
is heated to whiteness in iron retorts, connected with suitable recipients, 
in which the distilled metal is collected under a layer of naphtha. 

It is a silver-white metal, is rapidly tarnished in air, and becomes 
coated with a brownish yellow layer. At ordinary temperatures it is of 
waxy consistency; at 95.6° it fuses; at a white heat it volatilizes; sp. gr. 
0.972 at 15°. 

In air it is gradually oxidized from the surface inward, but may be 
kept in well-closed vessels without the protection of a layer of naphtha. 
It decomposes water; frequently, if the sodium have been long kept, with 
an explosion. It burns with a yellow flame. Its affinities are the same 
as, but less active than, those of potassium. 

Oxides. — Three oxides of sodium have been described, Na 4 0, Na 2 0, 
Na 2 2 . The protoxide, Na 2 0, is a grayish white mass, formed when 
sodium is burned in dry air, or by action of sodium upon sodium hydrate. 

Hydrate — Caustic soda — Soda (U. S., Br.) — NaHO — is formed 
when water is decomposed by sodium. It is usually obtained by decom- 
posing the carbonate with caustic lime or baryta. The solution is decanted 
from the earthy carbonate and evaporated in a silver basin, in which the 
residue is fused and cast into cylindrical moulds. It is purified by solu- 
tion in alcohol and evaporation. The soda by baryta is purer than the 
soda by lime / the latter frequently contains arsenic. 

It is opaque, white, fibrous, brittle, fusible below redness, sp. gr. 2.00; 
very soluble in water; its solutions, known in the arts as Soda lye, and in 
pharmacy as Liq. sodo3 (the latter of sp. gr. 1.071), are intensely caustic 
and alkaline. When exposed to air it absorbs water and is converted 
into the carbonate. 

Soda solutions attack glass very readily; the necks and stoppers of 
bottles containing them should be well coated with paraffine. 

Chloride — Common salt — Sea salt — Table salt — Sodii chloridum 
(U. S., Br.) — NaCl — occurs abundantly in nature, deposited in the solid 
form as rock salt, in solution in all natural waters, in suspension in the 
atmosphere, and as a constituent of almost all vegetable and animal 
tissues. It is formed in an infinite variety of chemical reactions. It is 
obtained from the natural deposits of rock salt; or by evaporation of sea- 
water or the water of saline springs. It is the source from which all the 
compounds of sodium are industrially obtained, directly or indirectly. 

It crystallizes in anhydrous cubes or octahedra; sp. gr. 2.078; fuses 
at a red heat, and crystallizes on cooling; at a white heat it volatilizes 
sensibly. One part of the salt dissolves in 2.78 parts of water at 14°; 
in 2.7 parts at 60°, and in 2.48 parts at 109.7°. Dilute solutions, on freez- 
ing, yield pure ice. Hydrochloric acid precipitates it from its concen- 
trated solution. It is insoluble in absolute alcohol, sparingly soluble 



sodium. 395 

in weak alcohol. Sulphuric acid decomposes it with formation of sodium 
sulphate and liberation of hydrochloric acid. 

Physiological. — Sodium chloride exists in every animal tissue and 
fluid, and is present in the latter, especially the blood, in tolerably con- 
stant proportion. It is introduced with the food, either as a constituent 
of the alimentary substances, or as a condiment. In the body it serv r es to 
aid the phenomena of osmosis and to maintain the solution of the albu- 
minoids. It is probable, also, that it is decomposed in the gastric mucous 
membrane with formation of free hydrochloric acid. 

It is discharged from the economy by all the channels of elimination, 
notably by the urine, when the supply by the food is maintained. If, 
however, the food contain no salt, it disappears from the urine before it 
is exhausted from the blood. 

The amount of chlorine (mainly in the form of sodium chloride) voided 
by a normal male adult in 24 hours is about 10 grams, corresponding to 
16.5 grams of sodium chloride. When normal or excessive doses are taken, 
the amount eliminated by the urine is less than that taken in; when small 
quantities are taken, the elimination is at first in excess of the supply. 
The hourly elimination increases up to the seventh hour, when it again 
diminishes. The amount of sodium chloride passed in the urine is less 
than the normal in acute, febrile diseases; in intermittent fever it is dim- 
inished during the paroxysms, but not during the intervals. In diabetes 
it is much increased, sometimes to 29 grams per diem. 

Quantitative determination of chlorides in urine. — The process is 
based upon the formation of the insoluble silver chloride, and upon the 
formation of the brown silver chromate in neutral liquids, in the absence 
of soluble chlorides. The solutions required are: 

First. — A solution of silver nitrate of known strength, made by dis- 
solving 29.075 grams of pure, fused silver nitrate (see p. 407) in a litre of 
water. Second. — A solution of neutral potassium chromate. 

To conduct the determination, 5 — 10 c.c. of the urine are placed in a 
platinum basin, 2 grams of sodium nitrate (free from chloride) are added; 
the whole is evaporated to dryness over the water-bath, and the residue 
heated gradually until a colorless, fused mass remains. This, on cooling, 
is dissolved in water, the solution placed in a small beaker, treated with 
pure, dilute nitric acid to faintly acid reaction, and neutralized with cal- 
cium carbonate. Two or three drops of the chromate solution are added, 
and then the silver solution from a burette, during constant stirring of 
the liquid in the beaker, until a faint reddish tinge remains permanent. 
Each c.c. of the silver solution used represents 10 milligrams of sodium 
choride (or 6.065 milligrams of chlorine) in the amount of urine used. 

Example. — 5 c.c. urine used, 6 c.c. silver solution added; 1,200 c.c. 

urine passed in 24 hours: .'.— — — - x 1,200 — 14.4 grams NaCl in 24 

5 

hours. 

If the urine contain iodides or bromides, they must be removed by 
acidulating the solution of the residue of incineration with sulphuric 
acid, removing the iodine or bromine by shaking with carbon disulphide, 
neutralizing the aqueous solution with calcium carbonate and proceeding 
as above. 

Bromide, NaBr. — formed by dissolving bromine in a solution of 
caustic soda to saturation, evaporating to dryness, calcining the residue 
at a dull red heat; redissolving in water, filtering and crystallizing. It 
crystallizes in anhydrous cubes; soluble in 1.13 parts of water at 20% 



396 GENERAL MEDICAL CHEMISTRY. 

and in 0.87 at 100°; soluble in alcohol. It contains 77. 67 per cent, of 
bromine. 

Iodide, Nal — prepared by heating together water, iron-filings, and 
iodine in fine powder, filtering, adding an equivalent quantity of sodium 
sulphate and some slacked lime; boiling, decanting, and evaporating. It 
crystallizes in anhydrous cubes; soluble in 0.56 parts of water at 20°, 
and in 0.32 at 100°; soluble in alcohol. It contains 84.66 per cent, of 
iodine. 

Salts of Sodium. — Nitrate — Cubic saltpetre — Chili saltpetre — Sodii 
nitras (U. S.) — N0 3 Na — occurs in natural deposits in Chili and Peru. It 
crystallizes in anhydrous rhombohedra; is deliquescent; has a cooling, 
saline, and somewhat bitter taste; fuses at 310°, and, when strongly 
heated, is decomposed with formation of nitrite, and then of hydrate of 
*odium and nitric acid; very soluble in water; less soluble in water con- 
taining fre% nitric acid; sparingly soluble in alcohol. 

It is used in the manufacture of saltpetre, in the manufacture of 
nitric acid, sodium sulphate being a byproduct, and as a fertilizer. 

Sulphates. — There are five sodium sulphates: S0 4 NaH, S0 4 Na 2 , S 2 
0,Na a , (SOJ.Na.H, and (SOJ.NaH,. 

Tlydrosodic sidphate — Acid sodium sulphate — Sodium bisidphate — S0 4 
NaH — crystallizes in long, four-sided prisms; is unstable, and is decom- 
posed by exposure to air, by water or by alcohol, into sulphuric acid and 
the neutral sulphate. When heated to dull redness, it is converted into 
the pyrosidphate, S 2 7 Na 2 , corresponding to pyrosulphuric or Nordhau- 
sen acid. 

Sodic sulphate — Neutral sodium sidphate — Glauber's salt — Sodii sul- 
phas (U. S.) — Sodce sulphas (Br.) — S0 4 Na 2 — occurs in nature in the solid 
form, and in solution in many natural waters. It is obtained as a step in 
the manufacture of the carbonate (q. v.), from the natural deposits, from 
the mother-liquors of the preparation of sodium chloride, and as a bypro- 
duct in the manufacture of nitric acid; principally by the decomposition 
of sodium chloride by sulphuric acid. 

It crystallizes with water in two proportions, 7 Aq. and 10 Aq. The 
salt, S0 4 Na 2 + 7Aq. is deposited from saturated or supersaturated solutions 
at + 5°. The salt, SO 4 Na 2 + 10 Aq. is that usually met with and which 
is used in pharmacy. It crystallizes in large, colorless, oblique, rhombic 
prisms, which effloresce in air and gradually lose all their Aq. It fuses 
at 33° in its water of crystallization, and is gradually converted into the 
anhydrous salt. If fused at 33° and allowed to cool, it remains liquid in 
supersaturated solution, from which it is deposited, the entire mass be- 
coming crystalline on contact with the smallest particle of foreign matter. 
It is sparingly soluble in alcohol. 

Physiological. — The neutral sulphates of sodium and potassium seem 
to exist in small quantity in all animal tissues and fluids, with the excep- 
tion of milk, bile, and gastric juice; they certainly exist in the blood and 
urine. They are partially introduced with the food, and in part formed 
in the body as a result of the metamorphosis of those constituents of the 
tissues which contain sulphur in organic combination. 

The principal elimination of the sulphates is by the urine. All the 
sulphuric acid in the urine is not in simple combination with the alkaline 
metals, a considerable amount exists in the form of the alkaline salts of 
conjugate, monobasic ether acids, which on decomposition yield an 
aromatic organic compound. The amount of sulphuric acid discharged 
by the urine in twenty-four hours, in the form of alkaline sulphates, is 



SODIUM. 397 

from 2.5 to 3.5 grams; that eliminated in the salts of the conjugate acids, 
0.617 to 0.094 gram. 

Hyposulphite — Sodii hyposidphis (U. S.) — S 2 3 Na., + 5Aq. — is ob- 
tained by fusing together sulphur and sodium carbonate ; oxidizing the 
sulphide so formed; dissolving sulphur in the hot, concentrated solution 
of the sulphite, and crystallizing. 

It crystallizes in large, colorless prisms, which fuse at 45°. One part 
dissolves in 1.44 part of water at 20°; and in 0.52 part at 60°., It is in- 
soluble in alcohol. Its solutions precipitate alumina from its salts with- 
out precipitating iron or manganese ; they dissolve many compounds 
which are insoluble in water; cuprous hydrate, iodides of lead, silver, and 
mercury, lead and calcium sulphates. It acts as a disinfectant, and is 
preservative of animal tissues. 

Silicates. — If silex and sodium carbonate be fused together, the 
residue extracted with water and the solution evaporated, a transparent, 
glass-like mass, soluble in hot water, remains ; this is soluble glass or 
tvater-glass. When exposed to the air in contact with stone, it becomes 
entirely insoluble, and is used to render stone structures imperme- 
able. 

Phosphates. — Three salts derived from orthophosphoric acid exist: 

Trisodic phosphate — Basic sodium phosphate — P0 4 Na 3 + 12Aq. — is 
obtained by adding sodium hydrate to disodic phosphate and evaporating 
to crystallization. It crystallizes in six-sided prisms; soluble in 5.1 parts 
of water at 15.5°. The solution is alkaline in reaction, and by exposure 
to air absorbs carbon dioxide with formation of disodic phosphate, and 
sodium carbonate. 

Disodic phosphate — Hydrodisoclic phosphate — Neutral sodium phos- 
phate — Phosphate of soda — Sodii phosphas (U. S.) — Sodce phosphas 
(Br.) — P0 4 Na 2 H-rl2Aq. — is obtained by converting tricalcic phosphate 
(bone phosphate) into monocalcic phosphate, and decomposing that salt 
with sodium carbonate. It crystallizes below 30° in oblique, rhombic prisms 
with 12 Aq. ; at 33°, it crystallizes with 7 Aq. The salt with 12 Aq. 
effloresces in air and readily parts with 5 Aq. ; it is soluble in four parts 
of cold water and in two parts of boiling water; that with 7 Aq. is not 
efflorescent and dissolves in eight parts of water at 23°. Its solutions are 
faintly alkaline. It is insoluble in alcohol. 

Monosodic phosphate — Acid sodium phosphate — P0 4 NaH 2 -[-Aq. — 
crystallizes in rhombic prisms. At 100° it loses its Aq., and, at about 200° 
is converted into an acid pyrophosphate, P 2 7 Na 2 H 2 , which at 204° is 
converted into the metaphosphate, P0 3 Na. It is very soluble in water 
and insoluble in alcohol. Its solutions are acid in reaction. 

Physiological. — All the sodium phosphates exist, accompanied by the 
corresponding potassium salts, in the animal economy. The disodic and 
dipotassic phosphates are the most abundant, and of these two the for- 
mer. They exist in every tissue and fluid of the body, and are more 
abundant in the fluids of the carnivora than in those of the herbivora. 
In the blood, in which the sodium salt predominates in the plasma, and 
the potassium salt in the corpuscles, they serve to maintain an alkaline 
reaction. With strictly vegetable diet the proportion of phosphates in 
the blood diminishes, and that of the carbonates (the predominating salts 
in the blood of the herbivora) increases. 

The monosodic and monopotassic phosphates exist in the urine, the 
former predominating, and to their presence the acid reaction of that 
fluid is largely due. They are produced by decomposition of the neutral 



398 GENERAL MEDICAL CHEMISTRY. 

salts by uric acid. The urine of the herbivora, whose blood is poor in 
phosphates, is alkaline in reaction. 

The greater part of the phosphates in the body are introduced with 
the food; a portion is formed in the economy by the oxidation of phos- 
phorized organic substances, the lecithins. (See p. 286). 

Borates. — Six sodium borates have been described; the only one re- 
quiring mention is Disodic tetraborate; Sodium pyroborate; Borate 
of sodium.; Borax; Tincal; Sodii boras (U. S.) — Bo 4 O 7 Na 2 + 10Aq. — is 
now prepared chiefly from the boracic acid of Tuscany, which is boiled 
with a proper quantity of sodium carbonate and crystallized. It crystal- 
lizes in hexagonal prisms with 10 Aq., or in regular octahedra with 5 Aq. 
The former variety is permanent in moist air, but effloresces in dry air, 
and is soluble in 12 parts of cold and in 2 parts of boiling water; the lat- 
ter is permanent in dry air. Either form, when heated, fuses in its Aq., 
and swells considerably; at a red heat it becomes anhydrous, and on 
cooling forms a clear, glassy mass. 

It is fatal to the lower forms of animal life, and is a safe and efficient 
asrent for driving off insect vermin. 

Hypochlorite, ClONa — is obtained in solution in the Liq. sodce 
chlorinates (U. S.); Liq. sodos chloratce (Br.); or Labarraque's solution, 
by decomposing a solution of chloride of lime (q. v.) with sodium carbonate 
and filtering. It is readily decomposed, giving up a portion of its chlo- 
rine, which, being in the nascent state, acts as an efficient decolorizing and 
disinfecting a^ent. 

Permanganate, Mn0 4 Na — is prepared in the same way as the po- 
tassium salt (q. v.), which it resembles in its properties. It enters into 
the composition of Candy's fluid, and of the disinfectant known as chloro- 
zone, which is a solution of sodium permanganate and hypochlorite. 

Acetate — Sodii acetas (U. S.) — Sodce acetas (Br.) — C 2 H 3 2 Na+3Aq. 
— is prepared by distilling purified calcium pyrolignite with sulphuric 
acid, neutralizing with sodium carbonate, and crystallizing. It crystal- 
lizes in large, colorless prisms; has a sharp, bitterish taste; is soluble in 
3.9 parts of water at 6°; soluble in alcohol; in dry air it loses 3 Aq., which 
it takes up again from moist air. Heated with soda-lime, it is decomposed 
with production of marsh-gas. The anhydrous salt, heated with sulphuric 
acid, yields glacial acetic acid. 

Carbonates. — Three sodium carbonates are known: C0 3 Na 2 , C0 3 Na 
H,(C0 3 ) 3 Na 4 H 2 . Sodium carbonate — Neutral carbonate of soda — Soda — 
Sal soda — Washing soda — Soda crystals — Sodii carbonas (U. S.) — Sodce 
carbonas (Br.) — C0 3 Na 2 — is industrially the most important of the sodium 
compounds, and is manufactured in enormous quantity from the chloride 
by Leblanc's or Solvay's processes; or from cryolite, a native fluoride of 
sodium and aluminium. 

Leblanc's process, in its present form, consists of three distinct pro- 
cesses: First. — The conversion of sodium chloride into the sulphate by 
decomposition by sulphuric acid. Second. — The conversion of the sul- 
phate into carbonate by heating a mixture of the sulphate with calcium 
carbonate and charcoal. The product of this reaction, known as black 
ball soda, is a mixture of sodium carbonate with charcoal and calcium 
sulphide and oxide. Third. — The purification of the product obtained in 
Second. The ball black is broken up, disintegrated by steam, and lixivi- 
ated. The solution, on evaporation, yields the soda salt or soda of com- 
merce. 

Of late years Leblanc's process has been in great part replaced by 



POTASSIUM. 399 

Solvay's method, or ammonia process, which is more economical and 
yields a purer product. In this process sodium chloride and ammonium 
bicarbonate react upon each other with production of the sparingly solu- 
ble sodium bicarbonate and the very soluble ammonium chloride. The 
sodium bicarbonate is then simply collected, dried, and heated, when it is 
decomposed into carbonate, water, and carbon dioxide. 

The anhydrous carbonate, Sodii carbonas exsiccata (U. S.), C0 3 Na 2 , 
is formed as a white powder by calcining the crystals. It fuses at dull 
redness and gives off a little carbon dioxide. It combines with and dis- 
solves in water with elevation of temperature. 

The crystalline sodium carbonate, CO 3 Na 2 -f-10Aq., forms large rhom- 
bic crystals, which effloresce rapidly in dry air; fuse in their Aq. at 34°; 
are soluble in water, most abundantly at 38°, at which temperature 100 
parts of water contain 51.67 parts of C0 3 Na 2 . The solutions are alkaline 
in reaction. 

JTydrosodic carbonate — Monosodic carbonate — Bicarbonate of soda — 
Acid carbonate of soda — Vichy salt — Sodii bicarbonas — (U. S.) — Sodas 
bicarbotias (Br.) — C0 3 NaH — exists in solution in many mineral waters. 
It is obtained by the action of carbon dioxide upon the disodic salt in 
the presence of water. 

It crystallizes in rectangular prisms, anhydrous and permanent in dry 
air; in damp air it gives off carbon dioxide and is converted into the 
sesquicarbonate, (C0 3 ) 3 Na 4 H 2 . When heated it gives off carbon dioxide 
and water, and leaves the disodic carbonate; 100 parts of water dissolve 
8.15 parts at 10°, and 16.4: parts at 60°; above 70° the solution gives off 
carbon dioxide. The solutions are alkaline. 

Physiological. — The fact that the carbonates of sodium and potassium 
are almost invariably found in the ash of animal tissues and fluids, is no 
evidence of their existence there in life, as the carbonates are produced 
by the incineration of the sodium and potassium salts of organic acids. 
There is, however, excellent indirect proof of the existence of the alka- 
line carbonates in the blood, especially of the herbivora, in the urine of the 
herbivora at all times, and in that of the carnivora and omnivora when 
food rich in the salts of the organic acids, with alkaline metals, is taken. 
The carbonates in the blood are both the mono- and disodic and potassic; 
and the carbonic acid in the plasma is held partially in simple solution, 
and partly in combination in the monometallic carbonates. 

Analytical Characters. — Hydrofluosilicic acid — a gelatinous pre- 
cipitate, if not too dilute. Potassium pyroantimoniate, in neutral solu- 
tion and in the absence of metals other than potassium and lithium, a 
white, flocculent precipitate, becoming crystalline on standing. Periodic 
acid in excess, a white precipitate if the solution be not too dilute. The 
Bunsen flame is colored yellow, and shows a brilliant double line occupy- 
ing the position of the D-line of the solar spectrum; A=5895 and 5889. 



POTASSIUM. 

Kalium K 39.137 

Is prepared by the same process as that used for obtaining sodium. It 
is a silver-white metal, brittle at 0°; waxy at 15°; at 62.5° it fuses; at 
a red heat it distils in green vapors, which condense in cubic crystals; sp. 
gr. 0.865 at 15°. 



400 GENERAL IMEDICAL CHEMISTRY. 

Potassium is the only metal which oxidizes at low temperatures in dry 
air, in which it is rapidly coated with a white layer of the hydrate, and 
frequently ignites, burning with a violet flame. It must be kept under 
naphtha. It decomposes water or ice with great energy, the reaction 
liberating heat enough to ignite the hydrogen which is set free. It com- 
bines with chlorine with incandescence, and also unites directly with sul- 
phur, phosphorus, arsenic, antimony, and tin. 

Oxides. — Two oxides of potassium are known, K 2 and K„0 4 . 

Hydrate — Potash — Potassa — Common caustic — Potassa (U. S.) — 
Potassa caustica (Br.) — KHO — is obtained from potassium carbonate by 
decomposition with calcic hydrate. The solution is evaporated and the 
residue fused and cast into cylindrical moulds; the product is potash by 
lime. To purify it, it is dissolved in alcohol, the solution evaporated, the 
residue fused in a silver basin and cast in a silver mould; the product is 
potash by alcohol, and is free from potassium chloride and sulphate, but 
contains small quantities of the carbonate, and frequently arsenic. 

It is usually met with in cylindrical sticks, hard, white, opaque, and 
brittle. The potash by alcohol has a bluish tinge, and a smoother sur- 
face than the common; sp. gr. 2.1; it fuses at dull redness; is freely 
soluble in water; less so in alcohol. The solutions have a soapy taste, 
and an alkaline reaction, and are strongly caustic. In air, it absorbs wa- 
ter and carbon dioxide, and is finally converted into the carbonate. Its 
solutions dissolve chlorine, bromine, iodine, sulphur, and phosphorus. 
It decomposes the ammoniacal salts with liberation of ammonia; and the 
salts of many of the metals with formation of a potassium salt and a 
hydrate of the metal. It dissolves the albuminoids with formation of an 
alkali albuminate; when heated with them, they are decomposed with 
formation of leucin, tyrosin, etc. It oxidizes the carbohydrates with 
formation of potassium carbonate and oxalate. 

Sulphides. — Five sulphides, K 2 S, K 2 S 2 , K 2 S 3 , K 2 S 4 , and K 2 S 5 , and a 
sulphydrate, KHS, are known. The pentasulphide, K 2 S 5 , is formed when 
excess of sulphur and potassium carbonate are fused together; the pro- 
duct is a brown mass, known as liver of sulphur, or Potassii sulphure- 
tum (U. S.); Potassa sulphurata (Br.). It is readily decomposed, and 
on contact with hydrochloric acid gives off hydrogen sulphide. 

Chloride — Sal digestivum Sylvii — KC1 — exists in nature, either pure 
or mixed with other chlorides; at Stassfurth, a double chloride of potas- 
sium and magnesium, KC1, MgCl 2 + 6Aq., called carnallite, is worked as a 
source of potassium compounds. 

It crystallizes in anhydrous cubes; permanent in air; 100 parts of wa- 
ter dissolve 29.23 parts at 0°, and 0.2738 part more for every degree of 
elevation of temperature. 

Bromide — Potassii bromidum (U. S., Br.) — KBr — is formed either 
by decomposing ferrous bromide by potassium carbonate, or by dissolv- 
ing bromine in solution of potassium hydrate. In the latter case, a mix- 
ture of bromide and bromate is obtained, and the latter is converted into 
bromide by calcining the product. 

It crystallizes in anhydrous cubes or tables; has a sharp, salty taste; 
is very soluble in water, sparingly so in alcohol. Chlorine decomposes it 
with liberation of bromine. It contains 67.22 per cent, of bromine. 

Iodide — Potassii iodidum (U. S., Br.) — KI — is obtained by satura- 
ting potash solution with iodine, evaporating, and calcining the resulting 
mixture of iodide and iodate with charcoal. The product is very liable 
to contain iodate and carbonate. 



POTASSIUM. 401 

It crystallizes in cubes, which are transparent if the iodide be pure; 
permanent in air, salty in taste; soluble to the extent of 100 parts, in 
73.5 parts of water at 12.5°, and in 45 parts at 120°. It dissolves in 5.5 
parts of alcohol of sp. gr. 0.85 at 12.5°. Chlorine and nitrous and nitric 
acids decompose it with liberation of iodine. It combines with many 
other iodides to form double iodides. 

Salts. — Nitrate — Nitre — Saltpetre — Potassii nitras (U. S.) — Potassvb 
nitras (Br.) — N0 3 K — exists naturally, and is formed artificially as a re- 
sult of the decomposition of nitrogenized organic substances. The more 
usual process for its preparation is the decomposition of the native sodium 
nitrate, either by a boiling solution of potassium carbonate, or by potas* 
sium chloride. 

It crystallizes in six-sided, rhombic prisms, which are grooved upon 
the surface. It dissolves in water with depression of temperature, and 
is more soluble in water containing sodium chloride; in alcohol it is very 
sparingly soluble. It fuses at 350°, without decomposition; at a temper- 
ature below redness it gives off oxygen, and is converted into the nitrite, 
N0 2 K; when further heated it is decomposed into nitrogen, oxygen, and 
a mixture of the oxides. The readiness with which it gives up its oxy- 
gen, when heated in presence of an oxidizable substance, renders it valu- 
able as an oxidizing 1 agent. 

Gunpowder is an intimate mixture of this salt with sulphur and car- 
bon, in such proportion that the nitre contains all the oxygen required for 
the combustion. 

Chlorate — Chlorate of potash — Potassii chloras (U. S.) — Potasses 
chloras (Br.) — C10 3 K — is prepared from potassium chloride; this is mixed 
with slaked lime, and the mixture, while heated to 60°, treated with 
chlorine until no further absorption of gas takes place, when it is drawn 
off, allowed to deposit, the clear solution rapidly evaporated, and the pro- 
duct purified by recrystallization. 

It crystallizes in transparent, anhydrous plates. Soluble in water to 
the extent of 6.03 parts in 100 at 15.37°, and 24 parts at 104.7°; spar- 
ingly soluble in weak alcohol; fuses at 400°; if further heated, it is de- 
composed into chloride and perchlorate with liberation of oxygen, and at 
a still higher temperature the perchlorate is decomposed into chloride 
and oxygen. 

It is a valuable source of oxygen, and a more active oxidizing agent 
than nitre. When mixed with readily oxidizable substances, carbon, sul- 
phur, phosphorus, sugar, tannin, resins, etc., the mixtures explode when 
heated or subjected to shock, the violence of the explosion being such as 
to prevent the use of such mixtures as explosives. With strong sul- 
phuric acid, potassium chlorate gives off peroxide of chlorine, C1 2 4 , an 
explosive, yellowish gas. Nitric acid decomposes it with formation of 
nitrate and perchlorate, and liberation of chlorine and oxygen. Heated 
with hydrochloric acid, it gives a mixture of chlorine and peroxide of 
chlorine, the latter acting as an energetic oxidant in solutions in which 
it is generated. 

Hypochlorite, C10K — is formed in solution by imperfect saturation 
of a cooled solution of potash with hypochlorous acid. An impure solu- 
tion is used in bleaching, under the name of Javelle icater. 

Sulphates. — Two sulphates, formed from single molecules of the 
acid, exist, S0 4 K 2 and S0 4 KH. Besides these, others are known, such 
as (S0 4 ) 3 K 4 H 2 , (S0 4 ) 2 K 3 H, and the pyrosulphate, S 2 7 K 2 . 

Sulphate — Dipotassio sulphate — Potassii sulphas — (U. S.) — Potasso3 
26 



402 GENERAL MEDICAL CHEMISTRY. 

sulphas — (Br.) — S0 4 K 2 — exists in the Stassfurth mines, in the ash of 
many plants, and in solution in mineral waters. It is obtained from the 
Stassfurth deposits, and as an accessory product in many chemioal manu- 
facturing processes. 

It crystallizes in right rhombic prisms; hard, permanent in air; salt 
and bitter in taste; soluble in water to the extent of 10.5 parts in 100 at 
12°, and 26.3 parts at 101.5°. 

Hydropotassic sulphate — Monopotassic sulphate — Acid sulphate — 
S0 4 KH — is formed as a by-product in the manufacture of nitric acid. 
When heated it loses water, and is converted into the pyrosulphate, 
S 2 7 K 2 , which, at a higher temperature, is decomposed into the dipotas- 
sic salt and sulphur trioxide. 

Sulphites. — Three sulphites, S0 3 K 2 , S0 3 KH, and S a 6 K 9 , are known. 

Sulphite — Dipotassic sulphite — Neutral potassium sulphite — JPotassii 
sulphis (U. S.) — S0 3 K 2 — is formed by saturating a solution of the carbo- 
nate with sulphur dioxide, and evaporating over sulphuric acid. It crys- 
tallizes in oblique rhombic octahedra, which have a sulphurous odor and 
are very soluble in water. Its solution, when exposed to air, absorbs 
oxygen, and the salt is converted into the sulphate. 

Chromate — Neutral chromate — Cr0 4 K 2 — is formed by heating a mix- 
ture of chrome iron ore, FeCr 2 4 , and potassium nitrate or carbonate in 
contact with air; the residue is extracted with water; the solution neu- 
tralized with dilute sulphuric acid and evaporated. The dichromate thus 
formed is dissolved in water and converted into the chromate by neu- 
tralization with a suitable quantity of potassium carbonate. 

Dichromate — Bichromate — Potassii bichromas (U. S.) — Potasses 
bichromas (Br.) — Cr 2 7 K 2 — is prepared as described above. It forms 
large, reddish orange colored, prismatic crystals; soluble in water; fuses 
below redness, and at a higher temperature is decomposed into oxygen, 
potassium chromate, and sesquioxide of chromium. Hydrochloric acid 
heated with it gives off chlorine. 

Permanganate — Potassii permanganas (U. S.) — Potassce perman- 
ganas (Br.) — Mn0 4 K — is obtained by fusing a mixture of manganese 
dioxide, potash, and potassium chlorate, and evaporating the solution to 
crystallization; potassium manganate and chloride are first formed; on 
boiling with water the manganate is decomposed into potassium perman- 
ganate and hydrate, and manganese dioxide. 

It crystallizes in dark prisms, almost black, with greenish reflections, 
which yield a red powder when broken. Soluble in water, communicat- 
ing to it a red color, even in very dilute solution. It is a most valuable 
oxidizing agent; with organic matter its solution is turned to green by 
the formation of the manganate, or deposits the brown sesquioxide of 
manganese, according to the nature of the organic substance; in some 
instances the reaction takes place best in the cold, in others under the 
influence of heat; in some better in acid solutions, in others in alkaline 
solutions. Mineral reducing agents act more rapidly. Its oxidizing 
powers render its solutions valuable as disinfectants. 

Acetate — Potassii acetas (U . S.) — Potassos acetas (Br.) — C 2 H 3 2 K — 
exists in the sap of plants; and it is by its calcination that the major part 
of the carbonate of wood ashes is formed. It is prepared by neutralizing 
acetic acid with carbonate or bicarbonate of potassium. 

It forms crystalline needles, deliquescent, and very soluble in water; 
less soluble in alcohol. Its solutions are faintly alkaline. 

Carbonates. — Dipotassic carbonate — Salt of tartar — Pearlash — Po~ 



POTASSIUM. 403 

tassii carbo7ias (U. S.) — Potasses carbonas (Br.) — C0 3 K 2 — exists in min- 
eral waters and in the animal economy. It is prepared industrially in an 
impure form, known as potash or pearlash, from wood ashes, from the 
molasses of beet-sugar, and from the native Stassfurth chloride. It is 
obtained pure by decomposing- the monopotassic salt, purified by several 
recrystallizations, by heat; or by calcining a potassium salt of an organic 
acid. Thus cream of tartar mixed with nitre and heated to redness 
yields a black mixture of carbon and potassium carbonate, called black 
flux; on extracting which with water, a pure carbonate, known as salt 
of 'tartar ', is left. 

It occurs as a white, granular, deliquescent powder; quite soluble in 
water; insoluble in alcohol. Its solutions are strongly alkaline. 

Hydropotassic carbonate — Monopotassic carbonate — Bicarbonate of 
potassium — Potassii bicarbonas (U. S.) — Potasses bicarbonas (Br.) — C0 3 
KH — is obtained by dissolving the carbonate in water and saturating the 
solution with carbon dioxide. It crystallizes in oblique rhombic prisms, 
much less soluble than the carbonate. In solution it is gradually con- 
verted into the dipotassic salt when heated, when brought into a vacuum, 
or when treated with an inert gas. The solutions are alkaline in reaction 
and in taste, but are not caustic. 

The substance used in baking, under the name salosratus, is this or 
the corresponding sodium salt. Its extensive use in some parts of the 
country is undoubtedly in great measure the cause of the prevalence of 
dyspepsia. When used alone in baking it " raises " the bread by decom- 
position into carbon dioxide and dipotassic (or disodic) carbonate, the 
latter producing disturbances of digestion by its strong alkaline re- 
action. 

Oxalates. — Three oxalates are known: Potassium oxalate — Neutral 
oxalate — C 2 4 K 2 -f- Aq., is formed when oxalic acid is saturated with potas- 
sium carbonate. It forms rhombic prisms, very soluble in water, insolu- 
ble in alcohol. Hydropotassic oxalate — Monopotassic oxalate — Binoxa- 
late of potash — C 2 4 KH. The salt of sorrel, or salt of lemon, is a mixture 
of this salt with the quadroxalate, C 2 4 HK,C 2 O 4 H 2 -b2Aq. It is used in 
straw-bleaching and for the removal of ink-stains. It closely resembles 
Epsom salt in appearance, and has been the cause of many cases of oxalic 
acid poisoning. 

Tartrates. — Potassic tartrate — Dipotassic tartrate — Soluble tar- 
tar — Neutral tartrate of potash — Potassii tartras (U. S.) — Potasses tartras 
(Br.) — C 4 H 4 6 K 2 — is prepared by neutralizing the hydropotassic salt 
with potassium carbonate. It forms a white, crystalline powder, very 
soluble in water, the solution being dextrogyrous, [«] D = +28.48°; soluble 
in 240 parts of alcohol. Acids, even acetic, decompose its solution with 
precipitation of the monopotassic salt. 

Hydropotassic tartrate— Monopotassic tartrate — Cream of tartar — 
Potassii bitartras (U. S.) — Potasses bitartras (Br.) — C 4 H 4 6 HK. During 
the fermentation of grape juice, as the proportion of alcohol increases, 
crystalline crusts collect in the cask. These constitute the crude tartar or 
argol of commerce, which is composed, in great part, of monopotassic tar- 
trate. The crude product is purified by repeated crystallization from 
boiling water; digesting the purified tartar with hydrochloric acid at 20°; 
washing with cold water, and crystallizing from hot water. 

It crystallizes in hard, opaque (translucent when pure), rhombic prisms, 
which have an acidulous taste, and are very sparingly soluble in water, 
still less soluble in alcohol. Its solution is acid, and dissolves many 



404 



GENERAL MEDICAL CHEMISTRY. 



metallic oxides with formation of double tartrates. When boiled with 
antimony trioxide, it forms tartar emetic. 

It is used in the household, combined with monosodic carbonate, in 
baking, the two substances reacting upon each other to form Rochelle 
salt with liberation of carbon dioxide. 

Baking -powders are now largely used as substitutes for yeast in the 
manufacture of bread. Their action is based upon the decomposition of 
hydrosodic carbonate by some salt having an acid reaction, or by a weak 
acid. In addition to the bicarbonate and Hour, or corn-starch (added to 
render the bulk convenient to handle and to diminish the rapidity of the 
reaction), they contain cream of tartar, tartaric acid, alum, hydrochloric 
acid, or acid phosphates. Sometimes ammonium sesquicarbonate is used, 
in whole or in part, in place of sodium carbonate. 

The reactions by which the carbon dioxide is liberated are the fol- 
lowing: 

1. C 4 H 4 O e HK + C0 3 NaH = C 4 H 4 6 NaK + H 2 + C0 2 . 



Hydropotassic 
tartrate 



Hydrosodic 
carbonate 



Sodium potassium 
tartrate. 



Water. 



Carbon 
dioxide. 



2. C 4 H 4 6 H 2 + 20O 3 NaH = C 4 H 4 6 Na 2 + 2H 2 + 2C0 2 

Tartaric acid. Hydrosodic Disodic tartrate. Water. Carbon 

carbonate. dioxide. 



3. (S0 4 ) 3 A1 2 ,S0 4 K 2 + 6C0 3 NaH = S0 4 K 2 + 3S0 4 Na 2 

Aluminium Hydrosodic Potassic Sodic 

potassium alum. 



Hydrosodic 
carbonate. 



Potassic 
sulphate. 



Sodic 
sulphate. 



+ A1 2 H 6 6 + 6C0 2 . 

Aluminium Carbon 

hydrate. dioxide. 



4. (S0 4 ) 3 A1 2 + 6C0 3 NaH = 3S0 4 Na, + A1 2 H 6 6 + 6CO s 



Aluminium 
sulphate. 



Hydrosodio 
carbonate. 



Sodic 
sulphate. 



Aluminium 
hydrate. 



Carbon 
dioxide. 



5. HC1 + C0 3 NaH 



NaCl + EL O + CO Q . 



Hydrochloric 
acid. 



Hydrosodio 
carbonate. 



Sodium 
chloride. 



"2 

Water. 



Carbon 
dioxide. 



6. P0 4 NaH 2 + C0 3 NaH = P0 4 Na 2 H + H 2 + C0 2 . 

Water. 



Monogodic 
phosphate. 



Hydrosodio 
carbonate. 



Disodic. 
phosphate. 



Carbon 
dioxide. 



7. 2(S0,) 9 A1, 

Aluminium 
sulphate. 



+ 3[2(C0 3 [NHJ 2 )CO a ] + 6H s O 

Ammonium Water, 

sesquicarbonate. 



= 6S0 4 (NH,) 2 + 



Ammonium 
sulphate. 



2A1,H 6 0, + 9CO,. 

Aluminium Carbon 

hydrate. dioxide. 



No. 1 is the reaction which takes place when cream of tartar and soda, 
or a baking-powder composed of those substances, are used in baking. 
The solid product of the reaction is Rochelle salt. No. 2 is that which 
occurs between tartaric acid and soda, and is but seldom utilized. No. 3 
is that between burnt potassium alum and soda. It is not utilized at 
present, as the ammonium alum is more economical. No. 4 is that which 
occurs in alum baking-powders, the burnt ammonia alum being prac- 
tically aluminium sulphate. The solid residues of the reaction are sodic 
sulphate and aluminium hydrate. No. 5 is a reaction very little used, 
owing to the inconvenience of handling a liquid, to the too rapid action 



POTASSIUM. 405 

of the substances upon each other, and to the danger of introducing 
arsenic with the acid. No. 6 is used to a certain extent, and has the ad- 
vantage that the solid residue of the reaction is a normal constituent of 
the body. No. 7 is occasionally utilized as an adjunct to No. 3. 

In our opinion, while yeast is to be preferred to any baking-powder, 
an alum-powder is in no way more liable to produce disturbances of 
digestion than one compounded of cream of tartar and soda. Referring 
to Equation 4, above, and taking the amount of powder generally used, 
35 grains per pound of bread, it will be seen that that amount of powder, 
containing 9.26 grains of aluminium sulphate, when neutralized during 
baking, produces 11.5 grains of Glauber's salt, 4.24 grains of aluminium 
hydrate, and 7.12 grains of carbon dioxide. On the other hand, a cream 
of tartar powder to produce, according to reaction above, the same quan- 
tity, 7.12 grains, of carbon dioxide, forms at the same time 33.98 grains of 
Rochelle salt. Assuming that one to two pounds is the average amount of 
bread consumed by an adult in twenty-four hours, there can be but little 
choice between taking on the one hand 4.24 — 8.48 grains of alumina and 
11.5 — 23.0 grains of Glauber's salt; and on the other hand, 33.98 — 67.96 
grains of Rochelle salt. Indeed, there is more danger to be apprehended 
from the tendency of repeated small doses of Rochelle salt to render the 
urine alkaline and thus favor the formation of phosphatic calculi, than 
from any supposed deleterious action of alumina, whose local action, even 
in considerable doses, is that of a very mild astringent, and whose ab- 
sorption is very doubtful. 

Sodium, potassium tartrate — Rochelle salt — Selde seignette — JPotassii et 
sodii tartras (U. S.) — Soda tartar ata (Br.) — C 4 H 4 6 NaK-f-4Aq.— is pre- 
pared by saturating hydropotassic tartrate with sodium carbonate. It 
crystallizes in large, transparent prisms, which effloresce superficially in 
dry air and attract moisture in damp air. It fuses at 70 — 80°, and loses 
3 Aq. at 100°. It is soluble in water, the solutions being dextrogyrous, 
[a] D = + 29.67°. 

Potassium antimonyl tartrate — Tartarated antimony — Tartar emetic — 
Antimonii et potassii tartras (U. S.) — Antimonium tartaratum — (Br.) — 
C 4 H 4 6 K(SbO)' — is prepared by boiling a mixture of 3 parts antimony tri- 
oxide and 4 parts hydropotassic tartrate in water for an hour, filtering, 
and allowing to crystallize; when required pure, it must be made from 
pure materials. 

It crystallizes in transparent, right rhombic octohedra, which turn 
white in air. It dissolves in 19 parts of water at 8.7°, and in 2.8° parts at 
100°. Its solutions are acid in reaction, have a nauseating, metallic 
taste, are kevogyrous, [a] D ~ 4-156.2°, and are precipitated by alcohol. 
The crystals contain \ Aq., which they lose entirely at 100°, and partially 
by exposure to air. It is decomposed by the alkalies, alkaline earths, 
and alkaline carbonates, with precipitation of antimony trioxide. The 
precipitate is redissolved by excess of soda or potash, or by tartaric acid. 
Hydrochloric, sulphuric, and nitric acids precipitate corresponding anti- 
monyl compounds from solutions of tartar emetic. It converts mercuric 
into mercurous chloride. It forms double tartrates with the tartrates of 
the alkaloids. 

Cyanide, CNK or KCy — is usually obtained from the ferrocyanide. 
The dried salt is mixed with dry potassium carbonate; the mixture is 
thrown into a red-hot iron crucible, and heated as long as effervescence 
continues; the fused mass is then decanted from the precipitated iron 
and allowed to solidify. 



406 GENERAL MEDICAL CHEMISTRY. 

It is usually met with in dull, white, amorphous masses; odorless 
when dry, it has the odor of hydrocyanic acid when moist. It is deli- 
quescent, and very soluble in water; almost insoluble in alcohol. Its solu- 
tion is acrid, and bitter in taste, with an after-taste of hydrocyanic acid. 
It is very readily oxidized to the cyanate, a property which renders it 
valuable as a reducing agent. Solutions of potassium cyanide dissolve 
iodine, silver chloride, the cyanides of silver and gold, and many metallic 
oxides. 

It is actively poisonous, and produces its effects by decomposition and 
liberation of hydrocyanic acid (q. v.). 

Ferrocyanide — Yellow prussiaie of potash — Potassiiferrocyanidum 
(U.S.) — Potassce prussias fava (Br.) — [Fe(CN) 6 ]K 4 + 3Aq. This salt, 
the source of the other cyanogen compounds, is manufactured by adding 
organic matter (blood, bones, hoofs, leather, etc.) and iron to potassium 
carbonate in fusion; or by other processes in which the nitrogen is ob- 
tained from the residues of the purification of coal-gas, from atmospheric 
air, or from ammoniacal compounds. 

It forms soft, flexible, lemon-yellow crystals, permanent in air at 
ordinary temperatures. They begin to lose water at 60°, and become 
anhydrous at 100°. Soluble in 2 parts of boiling water, and in 4 parts of 
cold water; insoluble in alcohol, which precipitates it from its aqueous 
solution. When calcined with potassium hydrate or carbonate, potas- 
sium cyanide and cyanate are formed, and iron is precipitated. Heated 
with dilute sulphuric acid, it yields an insoluble, white or blue salt, potas- 
sium sulphate, and hydrocyanic acid. Its solutions form with those of 
many of the metallic salts, insoluble ferrocvanides; those of zinc, lead 
and silver are white, cupric ferrocyanide is mahogany-colored, ferrous fer- 
rocyanide is bluish white, ferric ferrocyanide (Prussian blue), is dark 
blue. Blue ink is a solution of Prussian blue in a solution of oxalic acid. 

Ferricyanide — Red prussiate of potash — Fe 2 (CN) 12 K 6 — is prepared 
by acting upon the ferrocyanide with chlorine; or, better, by heating the 
white residue of the action of sulphuric acid upon potassium ferrocyanide, 
in the preparation of hydrocyanic acid, with a mixture of 1 volume of 
nitric acid and 20 volumes of water; the blue product is digested with 
water and potassium ferrocyanide, the solution filtered and evaporated. 

It forms red, oblique, rhombic prisms, almost insoluble in plcohol. 
With solutions of ferrous salts it gives a dark blue precipitate, Turn- 
bulVs blue. 

Analytical characters. — Platinic chloride in the presence of hy- 
drochloric acid, yellow precipitate, crystalline if formed slowly; sparingly 
soluble in water, much less in alcohol. Tartaric acid in not too dilute 
solution, white precipitate, soluble in alkalies and concentrated acids. 
Hydrofluosilicic acid, translucent, gelatinous precipitate; forms slowly, 
soluble in potash and in strong alkalies. Perchloric acid, white precipi- 
tate, sparingly soluble in water; insoluble in alcohol. Phosphomolybdic 
acid, white precipitate; forms slowly. Colors the flame of the Bunsen 
burner violet (the color is only observable in the presence of sodium 
through blue glass), and exhibits two bright lines, one in the red, one in 
the violet: A=7680 and 4045. 

Action of the sodium and potassium compounds upon the 
economy. — The hydrates of sodium and of potassium, and in a less de- 
gree the carbonates, disintegrate animal tissues, dead or living, with 
which they come in contact, and, by virtue of this action, act as power- 
ful caustics upon a living tissue. Upon the skin they produce a soapy 



SILVER. 407 

feeling and in the mouth a soapy taste. Like the acids, they cause death, 
either immediately, by corrosion or perforation of the stomach; or second- 
arily after weeks or months, by closure of one or both openings of the 
stomach, due to thickening consequent upon inflammation. 

The treatment consists in the neutralization of the alkali by an acid, 
dilute vinegar, or lemon-juice; or by an oil, olive-oil — or milk, with which 
it forms a soap. 

The other compounds of sodium, if the acid be not poisonous, are 
without deleterious action, unless taken in excessive quantity. Common 
salt has produced paralysis and death in a dose of half a pound. The neu- 
tral salts of potassium, on the contrary, are by no means without true 
poisonous action when taken internally, or injected subcutaneously in 
sufficient quantities, causing dyspnoea, convulsions, arrest of the heart's 
action, and death. In the adult human subject, death has followed the 
ingestion of doses of § ss. — 3 j. of the nitrate, in several instances; doses 
of 3 ij. — 3 ij« of the sulphate, have also proved fatal. 



SILVER. 
Argentum Ag 107.93 

Although silver is usually classed with the " noble metals," it differs 
from gold and platinum widely in its chemical characters, in which it 
closely resembles the alkaline metals. 

When pure silver is required, coin silver is dissolved in nitric acid and 
the diluted solution precipitated with hydrochloric acid. The silver 
chloride is washed until the washings no longer precipitate with silver 
nitrate; and reduced either: 1st, by suspending it in dilute sulphuric 
acid in a platinum basin, with a bar of pure zinc, and washing thoroughly 
after complete reduction; or, 2d, by mixing it with chalk and charcoal 
(AgCl, 100 parts, C, 5 parts, Co 3 Ca, 70 parts) and gradually introduc- 
ing the mixture into a red-hot crucible. 

Silver is a white metal; sp. gr. 10.47 — 10.54; fusible at 1000°; very 
malleable and ductile; the best known conductor of heat and electricity. 
It is not acted on by pure air, but is blackened in air containing a trace 
of hydrogen sulphide. Chlorine, bromine, iodine, sulphur, selenium, phos- 
phorus, and arsenic combine with it directly. Hot sulphuric acid dis- 
solves it as sulphate, and nitric acid as nitrate. The caustic alkalies do 
not affect it. It alloys readily with many metals; its alloy with copper 
is harder than the pure metal. 

Oxides. — Three oxides of silver are known: Ag 4 0, Ag 2 0, and Ag„0 2 . 

Silver monoxide — Protoxide — Argenti oxidum (U. S., Br.) — Ag 2 
— formed by precipitating a solution of silver nitrate with potash. It is 
a brownish powder; faintly alkaline and very slightly soluble in water; 
strongly basic. It readily gives up its oxygen. On contact with ammo- 
nium hydrate it forms a fulminating powder. 

Chloride, AgCl — formed when hydrochloric acid or a chloride is 
added to a solution containing silver. It is white; turns violet and black 
in sunlight; volatilizes at 260°; sparingly soluble in hydrochloric acid; 
soluble in solutions of the alkaline chlorides, hyposulphites, and cyanides, 
and in ammonium hydrate. 

Bromide, AgBr, and Iodide, Agl — are yellowish precipitates, formed 
by decomposing silver nitrate with potassium bromide and iodide. 



408 GENERAL MEDICAL CHEMISTRY. 

Salts. — Nitrate — Argenti nitras (U. S., Br.) — N0 3 Ag — is prepared 
by dissolving silver in nitric acid, evaporating, fusing, and recrystallizing. 
It crystallizes in anhydrous, right rhombic plates; soluble in one part of 
cold water, in 0.5 part of boiling water. The solutions are colorless and 
neutral. In the presence of organic matter it turns black. The fused 
salt, cast into cylindrical moulds, furnishes the Argenti nitras fusa (U. S.), 
lapis inf emails, or lunar caustic of pharmacy. If, during fusion, the tem- 
perature be raised too high, it is first decomposed into nitrite, oxygen, 
and silver, and, finally, leaves pure silver. 

Dry chlorine and iodine decompose it with liberation of anhydrous 
nitric acid. It absorbs ammonia to form a white substance, N0 3 Ag, 
3NH 3 , which, when heated, gives up its ammonia. Its solution is decom- 
posed very slowly by pure hydrogen, with deposition of silver. 

Silver nitrate is used in photography, in the manufacture of hair- 
dyes, and of marking-ink, and in the silvering of glass. 

Cyanide — Argenti cyanidum (U. S.) — AgCN — is prepared by pass- 
ing hydrocyanic acid through a solution of silver nitrate. It is a white, 
tasteless powder; gradually turns brown on exposure to light; insoluble 
in dilute acids; soluble in ammonium hydrate, and in solutions of ammo- 
niacal salts, cyanides, and of sodium hyposulphite. The mineral acids 
decompose it with liberation of hydrocyanic acid. 

Analytical Characters. — Hydrochloric acid, white, flocculent pre- 
cipitate, insoluble in nitric acid, readily soluble in ammonium hydrate. 
Potash or soda, brown precipitate, insoluble in excess, soluble in ammo- 
nium hydrate. Ammonium hydrate, from neutral solutions, brown 
precipitate, soluble in excess. Hydrogen sulphide or ammonium sulphy- 
drate, black precipitate, insoluble in the last-named reagent. Potassium 
bromide, yellowish white precipitate, insoluble in acids, if not very 
abundant, soluble in ammonium hydrate. Potassium iodide, same as 
bromide, but less soluble in ammonium hydrate. 

Action on the economy. — Silver nitrate acts both locally as a cor- 
rosive, and systematically as a true poison. Its local action is due to its 
decomposition by contact with organic substances, resulting in the separa- 
tion of elementary silver, whose deposition causes a black stain, and libera- 
tion of free nitric acid, which acts as a caustic. When absorbed, it causes 
nervous symptoms, referable to its poisonous action. The blue coloration 
of the skin, observed in those to whom it is administered for some time, 
is due to the reduction of the metal under the combined influence of light 
and organic matter; especially of the latter, as the darkening is observed, 
although it is less intense, in internal organs. 

In acute poisoning by silver nitrate, sodium chloride or white of egg 
should be given; and, if the case be seen before the symptoms of corrosion 
are far advanced, emetics. 



AMMONIUM COMPOUNDS. 

Ammonium (NH 4 ) 

Although the radical ammonium has probably never been isolated, 
there can remain but little doubt that such a radical exists in combination 
in the ammoniacal compounds. The ammonium hypothesis is based upon 
the following facts: 1st, when ammonia gas comes in contact with an acid 
gas, the two unite, without liberation of hydrogen, to form an ammoni- 



AMMONIUM COMPOUNDS. 409 

acal salt; 2d, the diatomic anhydrides unite directly with dry ammonia, 
with formation of the ammonium salt of an amido-acid: 

S0 3 + 2NH 3 = S0 3 (NH 2 )(NH 4 ) 

Sulphur trioxide. Ammonia. Ammonium sulphamate. 

3d, when solutions of the ammoniacal salts are subjected to electrolysis, a 
mixture having the composition NH 3 + H is given off at the negative pole; 
4th, amalgam of sodium, in contact with a concentrated solution of am- 
monium chloride, increases much in volume, and is converted into a light, 
soft mass, having the lustre of mercury. This ammonium amalgam is 
decomposed gradually, giving off ammonia and hydrogen in the propor- 
tion NH 3 + H; 5th, if the gases NH 3 -bH, given off by decomposition of 
the amalgam, exist there in simple solution, the liberated hydrogen 
would have the ordinary properties of that element; if, on the other hand, 
they exist in combination, the hydrogen would exhibit the more energetic 
affinities of an element in the nascent state. The hydrogen so liberated 
is in the nascent state. 

Oxide and Hydrate. — Neither the oxide of ammonium (NH 4 ) 2 0, 
nor its hydrate, NH 4 HO, has as yet been isolated, both being probably 
decomposed into ammonia and water immediately they are liberated. 

The hydrate, NH 4 HO — is considered as existing in the so-called aque- 
ous solutions of ammonia, which are clear liquids, lighter than water, 
have the taste and odor of ammonia, and are strongly alkaline in reac- 
tion. The Aqua ammonias fortior (U. S.) is of sp. gr. 0.900, and con- 
tains 249.5 grams NH 3 per litre; that of the British Pharmacopoeia is of 
sp. gr. 0.891, and contains 277 grams NH 3 per litre. The Aqua am- 
monia? (U. S.) is of sp. gr. 0.960, and contains 93.1 grams NH 3 per litre; 
that of the British Pharmacopoeia is of sp. gr. 0.950, and contains 118.0 
grams NH 3 per litre. 

Sulphides. — Ammonium forms four sulphides (NH 4 ) 2 S, (NH 4 ) 2 S 2 , 
(NH 4 ) 2 S 4 , and (NH 4 ) 2 S 5 ; and a sulphydrate (NH 4 )HS. 

The sulphydrate, NH 4 HS — is formed in solution, for use as a reagent 
in analysis, by saturating an aqueous solution of ammonium hydrate, pro- 
tected from air, with hydrogen sulphide. 

The sulphides of ammonium are also formed during the decomposition 
of nitrogenous organic substances, and exist in the gases discharged 
from burial-vaults, sewers, etc. 

Chloride — Muriate of ammonia — Sal-ammoniac — Ammonii chlorl- 
dum (U. S., Br.) — NH 4 C1 — is obtained from the ammoniacal water of 
gas-works, which contains ammonium carbonate and tarry substances. It 
is a translucid, fibrous, and elastic solid, salty in taste and neutral in re- 
action; volatilizes without fusion and without decomposition; 100 parts 
of water dissolve 37.28 parts of the salt at 20°, and 77.24 parts at 110°. 
Its solutions are neutral, but lose ammonia and become acid when boiled. 

Ammonium chloride exists in minute quantities in the gastric juice of 
the sheep and dog. It has also been said to occur in the perspiration, 
urine, saliva, and tears, which contain some ammonium compound in 
small quantity, but whether it is the chloride or another is not determined 
with certainty. 

Bromide — Ammonii bromidum (U. S., Br.), NH 4 (Br.) — is formed 
either by combining ammonia and hydrobromie acid; or by decomposing 
ferrous bromide with aqua ammonia?; or by double decomposition be- 
tween potassium bromide and ammonium sulphate. It is a white, granu- 



410 GENERAL MEDICAL CHEMISTRY. 

lar powder, or in large prisms, which turn yellow on exposure to air; 
soluble in 1.29 parts of water. It volatilizes without decomposition. It 
contains 81.63 per cent, of bromine. 

Iodide — Ammonii iodidum (U. S.), NH 4 I — is formed by the union 
of equal volumes of ammonia and hydriodic acid, or by double decom- 
position of potassium iodide and ammonium sulphate. It crystallizes in 
cubes; deliquescent; soluble in 0.60 parts of water. It contains 87.58 per 
cent, of iodine. 

Salts of ammonium. — Nitkate — Ammonii nitras (U. S.) — N0 3 
(NH 4 ) — is prepared by neutralizing- nitric acid with ammonium hydrate 
or carbonate. It forms flexible, anhydrous, six-sided prisms; soluble in 
0.5 parts of water at 18°; fuses at 150°, and decomposes at 210° with 
formation of nitrous oxide: N0 3 (NH 4 ) = N 2 + 2H 2 O. Ammonia and nitro- 
gen di- and tetroxides are also formed if the heat be suddenly applied or 
allowed to rise too high. When fused it is an active oxidant. 

Sulphates. — Amnionic sulphate — Diammonic sulphate — Neutral 
ammonium sulphate — Ammonii sulphas (U. S.) — S0 4 (NH 4 ) 2 — is manufac- 
tured from the ammoniacal gas liquids. These are distilled with milk of 
lime, and the product directed into dilute sulphuric acid; or the crude 
liquid is passed through filters charged with gypsum, when calcium car- 
bonate and ammonium sulphate are formed. It forms anhydrous rhombic 
crystals, quite soluble in water; fuses at 140°, and is decomposed at 200° 
into ammonia and mono-ammonic sulphate. 

Hydro -amnionic sulphate — Mono-ammonic sulphate — JBisidphate of 
ammonia, S0 4 H(NH 4 ) — is formed by the action of sulphuric acid upon 
diammonic sulphate. It crystallizes in right rhombic prisms, soluble in 
water and in alcohol. 

Acetate — C 2 H 3 2 (NH 4 ) — is formed by saturating acetic acid with 
ammonia, or with ammonium carbonate. It is white, odorless, very solu-> 
ble in water and in alcohol; fuses at 86°, and gives oif ammonia, then 
acetic acid, and finally acetamide. Its aqueous solution is used in medi- 
cine under the names Liq. ammonii acetatis ; Spirit of Minder er us. 

Carbonates. — Ammonia carbonate — Diammonic ca?'bonate — Neutral 
ammonium carbonate, C0 3 (NHJ 2 + Aq. — has recently been prepared as 
a crystalline solid. When exposed to air it is decomposed into ammonia 
and the monoammonic salt. 

Hydroammonic carbonate — Monoammonic carbonate — Acid carbo- 
nate of ammonia, C0 3 H(NH 4 ) — is prepared by saturating a solution of 
ammonium hydrate or sesquicarbonate with carbon dioxide. It crystal- 
lizes in large, rhombic prisms; soluble to the extent of 21 parts in 100 
in water at 20°; at 60° it is decomposed into ammonia and carbon di- 
oxide. 

Ammonium sesquicarbonate — Sal volatile — Ammonii carbonas (U. S.) 
— Ammonim carbonas (Br.) — (C0 3 ) 3 (NH 4 ) 4 H 2 + Aq. — the commercial car- 
bonate of ammonia, prepared by heating a mixture of ammonium chloride 
and chalk, and condensing the product; crystallizes in rhombic prisms; 
has an ammoniacal odor and an alkaline reaction; soluble to the extent of 
25 parts in 100 of water at 13°. By exposure to air or by heating its solu- 
tion, it is decomposed into water, ammonia, and monoammonic carbonate. 

Analytical characters. — The compounds of ammonium are odorless 
and entirely volatile at moderately elevated temperatures. Heated with 
potash, they give oif ammonia, recognizable, 1st, by changing moist, red 
litmus paper blue; 2d, by its odor; and, 3d, by forming white clouds on 
contact with a glass rod moistened with hydrochloric acid. 



♦ 



CALCIUM. 411 

"With platinic chloride, a yellow, crystalline precipitate. With Ay- 
drosodic tartrate in moderately concentrated and neutral solutions, a 
white, crystalline precipitate. 

Action on the Economy. — Solutions of the hydrate and carbonate 
act upon animal tissues in the same way as do the corresponding potas- 
sium and sodium compounds. They, moreover, disengage gaseous am- 
monia, which rapidly causes intense dyspnoea, irritation of the air-passa- 
ges, and suffocation. 

The treatment indicated is the neutralization of the alkali by a dilute 
acid. Usually the vapor of acetic acid or of dilute hydrochloric acid 
must be administered by inhalation. 



III. CALCIUM GROUP. 

Metals of the Alkaline Earths. 

Calcium, Ca, 40; Strontium, Sr, 87.5; Barium, Ba, 137.2. 

The members of this group are divalent in all their compounds; each 
forms two oxides, MO and M0 2 ; each forms a hydrate possessed of well- 
marked basic properties. 

CALCIUM. 
Ca 40 

Calcium is a light yellow metal; hard, very ductile; fusible at a red 
heat; not sensibly volatile; sp. gr. 1.984. It is not altered in dry air, but 
is converted into the hydrate in moist air. 

Oxides. — Calcium protoxide — Quick-lime — Calx (U. S., Br.) — CaO — 
is prepared industrially by heating a natural calcium carbonate; when 
required pure, by heating a carbonate, obtained by precipitation. 

It occurs in white or grayish, amorphous masses, odorless, alkaline 
and caustic; sp. gr. 2.3; almost infusible. With water, it is converted 
into the hydrate; the union is attended with great elevation of tempera- 
ture, and is known as slaking. In air, lime becomes air-slaked, and is 
converted into a white powder, a hydrocarbonate, CQ 3 Ca,CaH 2 2 . 

Calcium hydrate — Slacked lime — Calcis hydras (Br.) — CaH„0 2 — is 
prepared by the action of water upon quick-lime. If the quantity of 
water used be one-third that of the oxide, the hydrate is formed as a 
dry, white powder, odorless, alkaline in taste and reaction. It is more 
soluble in cold than in hot water. 

Lime-water — Liquor calcis (U. S., Br.) — is a solution of the hydrate 
in water. The solubility of calcium hydrate is diminished by the alka- 
lies, and is increased by sugar and mannite. The Liq. calcis saccharatus 
(Br.) is a solution of the hydrate, or of calcium saccharate, in solution of 
cane-sugar. Milk of lime is lime-water with an excess of hydrate. Cal- 
cium hydrate absorbs carbon dioxide. 

Chloride — Calcii chloridum (U. S., Br.) — CaCl 2 + 6Aq. — is obtained 
by dissolving marble in hydrochloric acid; is a bitter substance; deliques- 
cent and very soluble in water; when fused it loses all its Aq. and 
forms a white, amorphous mass; used as a drying agent. 



412 GENERAL MEDICAL CHEMISTRY. 

Chloride of lime — Bleaching -powder — Calx ehlorinata (U. S.) — 
Calx chlorata (Br.) — is a mixture composed principally of calcium chlo- 
ride, CaCl 2 , and hypochlorite, (C10) 2 Ca; prepared by passing chlorine 
over slaked lime maintained in excess. It is a grayish white powder, 
having a bitter, acrid taste; soluble in cold water; decomposed by boiling 
water; readily decomposed, with liberation of chlorine, by the weakest 
acids; carbon dioxide decomposes it with formation of calcium carbonate 
and liberation of hypochlorous acid, if it be moist; or of chlorine, if it 
be dry. 

Salts. — Sulphate, S0 4 Ca. — The hydrated compound, S0 4 Ca+ 2Aq., 
occurs as gypsum, in right rhombic prisms; frequently grouped in arrow- 
head shaped macles; sparingly soluble in water; more soluble in water 
containing free acid or chlorides; insoluble in alcohol. Ground gypsum 
is used in the arts under the name terra alba. At 80°, or more rapidly 
between 120° and 130°, it loses its Aq. and is converted into an opaque, 
white mass, which, when ground, is plaster-of- Paris. 

The setting of plaster when mixed with water is caused by the con- 
version of the anhydrous into the crystalline, hydrated salt. Plaster sur- 
faces are rendered smooth, dense, and capable of taking a high polish by 
adding glue and alum, or an alkaline silicate, to the water. 

Phosphates. — Three phosphates of calcium are known: (P0 4 ) a Ca 3 , 
(P0 4 H) s Ca s , and (P0 4 H,),Ca. 

Tricalcic phosphate — Tribasic or neutral phosphate — Bone phosphate 
— Calcis phosphas prmcipitata (U. S.) — Calcis phosphas (Br.) — (P0 4 ) 2 
Ca 3 — This salt occurs in soils, in coprolites, in guano, in all plants, and 
in every tissue and fluid of animal bodies. It is obtained by dissolving 
bone-ash in hydrochloric acid, filtering, and precipitating with ammonium 
hydrate; or by double decomposition between calcium chloride and an 
alkaline phosphate. When freshly precipitated it is gelatinous; when 
dry, it is a. light, white, amorphous powder; almost insoluble in pure 
water; soluble to a slight extent in water containing ammoniacal salts, 
or chloride or nitrate of sodium; readily soluble in dilute acids, even in 
water charged with carbon dioxide. Sulphuric acid decomposes it into 
calcium sulphate and monocalcic phosphate. Bone-ash is an impure tri- 
calcic phosphate, used in the manufacture of phosphorus and of super- 
phosphate (see below). 

Dicalcic phosphate, (P0 4 H) 2 Ca 2 +2H 2 O — a crystalline, insoluble salt; 
formed by double decomposition between calcium chloride and disodic 
phosphate in acid solution. 

Monocalcic phosphate — Acid calcium phosphate — Superphosphate of 
lime — (P0 4 H 2 ) 2 Ca — exists in brain-tissue and in acid animal fluids. It is 
formed when the tricalcic salt is dissolved in an acid, and is manufactured 
for use as a manure, by decomposing bone-ash with sulphuric acid. It 
crystallizes in pearly plates; very soluble in water, the solution being 
acid. 

Physiological. — All three calcium phosphates, accompanied by the 
corresponding magnesium salts, exist in the animal economy. The tri- 
calcic salt occurs in all the solids of the body and in all fluids not having 
an acid reaction, being held in solution in the latter by the presence of 
chlorides. In the fluids it is present in very small quantity, except in the 
milk, in which it is comparatively abundant; 2.5 to 3.95 parts per 1,000 in 
human milk, and 1.8 to 3.87 parts per 1,000 in cow's milk; constituting 
about 70 per cent, of the ash. The bones contain about 35 parts of 
organic matter, combined with 65 parts of mineral material. The average 



CALCIUM. 



413 



composition of human bone-ash is tricalcic phosphate, 83.89; calcium car- 
bonate, 13.03; calcium combined with chlorine, fluorine, and organic 
acids, 0.35; fluorine, 0.23; chlorine, 0.18. The average quantity of tri- 
calcic phosphate in male adult bones is 57 per cent.; that of calcium car- 
bonate, 10 per cent.; and that of trimagnesic phosphate, 1.3 per cent. In 
pathological conditions the composition of bone is modified as shown in 



the following table: 



Analyses of Bones. 





af ® 


efo" 


cSO 


* <J) 






ri 


oT t- 






s- 

o 


' 3 « 
a to 


■gffl 

■3 d) 


03 5 

"5 > 


•i-i 


.fl 


3 


"3 ° 




In 100 parts. 


ill 


S 83 * 


S« J 


a- 


. tn 


00 . 

'43 00 




«*-i-gi 






O 4) !3 


Oii ? S 


o »a 


«3 a 




DO 
83 




* r »h 

3*3 









56.9 


48.83 
29.18 
17.56 


32.54 

4.15 

53.25 


75.22 

6.12 

12.56 


72.20 
7.20 

14.78 
1.00 


■I 81.12 j- 
15.60 


£5.69 
3.00 

1 51 .53 


41.42 
8.36 

44.05 


19.58 




1.23 




72.63 


Calcium carbonate 


10.2 
1.3 


3.04 
0.23 


7.49 
1.22 


3.20 
0.92 


3.00 
0.80 


2.66 

* 


5.44 
3.43 


3.45 
1.02 


4.03 




1.93 




35.8 
64.2 


0.37 

78.01 
21.20 


1.35 

36.69 
63.31 


1.98 

81.34 
19.66 


1.02 

79.40 
20.60 


62 

81.12 

18.88 


0.91 

38.69 
61.31 


1.70 

49.78 
50.22 


0.61 




20.80 


Ash 


79.20 










a 


«3 


*a 


•d 




"oj 




sj 


* Included in tricalcic phos- 
phate. 


S 


& 

S 

JB 


.a 

n 


a 

83 
U 


a 

03 

o 
53 


to 


C S 'O 

d 


S* OS'S 
w 


3 




u 


^3 


o 


cS 




03 


01 05 









psi 


A 


t> 


3 


3 


fi 


n * 


> 



The teeth consist largely of tricalcic phosphate. Von Bibra gives for 
the enamel of the molars in man, 89.82 per cent, of this salt, and for the 
dentine, 66.72 per cent. 

From the urine, tricalcic phosphate is frequently deposited, either in 
the form of an amorphous, granular sediment, or as calculi. The dicalcic 
salt occurs occasionally in urinary sediments, in the form of needle- 
shaped crystals arranged in rosettes, and also in urinary calculi. The 
monocalcic salt is always present in acid urine, constituting, with the 
corresponding magnesium salt, the earthy phosphates. The total elimina- 
tion of phosphoric acid by the urine is about 2.75 grams in twenty-four 
hours, of which two-thirds is in combination with alkaline metals, and one- 
third in the phosphates of calcium and magnesium. The hourly elimina- 
tion follows about the same variation as that of the chlorides. The total 
elimination is greater with animal than with vegetable food; is diminished 
during pregnancy; and is above the normal during excessive mental work. 
The elimination of earthy phosphates is greatly increased in osteomala- 
cia, often so far that they are in excess of the alkaline phosphates. 

So long as the urine is acid, it contains the soluble acid phosphates; 
when the reaction becomes alkaline, or even on loss of carbon dioxide by 
exposure to air, the acid phosphate is converted into the insoluble trical- 
cic phosphate. Alkaline urines are for this reason almost always turbid, 
and become clear on the addition of acid. It is in such urine that phos- 
phatic calculi are invariably formed, usually about a nucleus of uric acid 
or of a foreign body. If the alkalinity be due to the formation of ammo- 
nia, the trimagnesic phosphate is not formed, but ammonio-magnesium 
phosphate (q. v.). 

A process for determining the quantity of phosphates in urine is 



414 GENERAL MEDICAL CHEMISTRY. 

based upon the formation of the insoluble uranium phosphate, and upon 
the production of a brown color when a solution of a uranium salt is 
brought in contact with a solution of potassium ferrocyanide. Four so- 
lutions are required: 1st, a standard solution of disodic phosphate; 
made by dissolving 10.085 grams of crystallized, non-effloresced disodic 
phosphate in water, and diluting to a litre; 2d, an acid solution of 
sodium acetate, made by dissolving 100 grams sodium acetate in water, 
adding 100 c.c. glacial acetic acid, and diluting with water to a litre; 
3d, a strong solution of potassium ferrocyanide; 4th, a standard so- 
lution of tiranium acetate, made by dissolving 20.3 grams of yellow ura- 
nic oxide in glacial acetic acid, and diluting with water to nearly a litre. 
Solution 1 serves to determine the true strength of this solution, 
as follows: 50 c.c. of Solution 1 are placed in a beaker, 5 c.c. of Solu- 
tion 2 are added, the mixture heated on a water-bath, and the uranium 
solution gradually added from a burette until a drop from the beaker 
produces a brown color when brought in contact with a drop of the fer- 
roc}-anide solution. At this point the reading of the burette, which indi- 
cates the number of c.c. of the uranium solution, corresponding to 
0.1 — P„0 5 , is taken. A quantity of water, determined by calculation 
from the result thus obtained, is then added to the remaining uranium 
solution, such as to render each cubic centimetre equivalent to 0.005 
gram phosphoric anhydride. 

To determine the total phosphates in a urine: 50 c.c. are placed in 
a beaker, 5 c.c. sodium acetate solution are added; the mixture is 
heated on the water-bath, and the uranium solution delivered from a 
burette until a drop, removed from the beaker and brought in contact 
with a drop of ferrocyanide solution, produces a brown tinge. The bu- 
rette reading, multiplied by 0.005, gives the amount of phosphoric anhy- 
dride in 50 c.c, urine; and this, multiplied by •£$ the amount of urine 
passed in 24 hours, gives the daily elimination. 

To determine the earthy phosphates, a sample of 100 c.c. urine is ren- 
dered alkaline with ammonia and set aside for 12 hours; the precipitate 
is then collected upon a filter, washed with ammoniacal water, brought 
into a beaker, dissolved in a small quantity of acetic acid; the solution 
diluted to 50 c.c. with water, treated with 5 c.c. sodium acetate solution, 
and the amount of phosphoric anhydride determined as above. 

Carbonates. — Calcium carbonate — Galcis carbonas prwcipitata 
(U. S., Br.) — C0 3 Ca — the most abundant of the natural compounds of 
calcium, exists as limestone, calk spar, chalk, marble, Iceland spar, and 
arragonite, and forms the mineral basis of the corals, shells of Crustacea, 
and of molluscs, etc. 

The precipitated chalk, Calcii carbonas prcecipitata (U. S., Br.), is pre- 
pared by precipitating a solution of calcium chloride with one of sodium 
carbonate. Prepared chalk, Creta prmparata (U. S., Br.), is native 
chalk, purified by grinding with water, diluting, allowing the coarser 
particles to subside, decanting the still turbid liquid, collecting, and dry- 
ing the finer particles; a process known as elutriation. 

It is a white powder, almost insoluble in pure water; much more sol- 
uble in water containing carbonic acid, the solution being regarded as 
containing hydrocalcic carbonate (C0 3 ) 2 H 2 Ca. At a red heat it 3'ields 
carbon dioxide and calcic oxide. It is decomposed by acids with liber- 
ation of carbon dioxide. 

Physiological. — Calcium carbonate is much more abundant in the 
lower than in the higher forms of animal life. It occurs in the egg-shells 



BATCIUM. 415 

of birds, in the bones and teeth of all animals; in solution in the saliva 
and urine of the herbivora, and deposited in the crystalline form, as oto- 
liths, in the internal ear of man. It is deposited pathologically in calcifi- 
cations, in parotid calculi, and occasionally in human urinary calculi and 
sediments. 

Oxalate — Oxalate of lime — C 2 O 4 0a — exists in the sap of many 
plants, and is formed as a white, crystalline precipitate by double decom- 
position between a calcium salt and an alkaline oxalate. It is insoluble 
in water, acetic acid, or ammonium hydrate; soluble in the mineral acids 
and in solution of acid sodium phosphate. 

Physiological. — Calcium oxalate is taken into the body in vegetable 
food, and is formed in the economy, where its production is intimately 
connected with that of uric acid. 

It occurs in the urine, in which it is increased in quantity when large 
amounts of vegetable food are taken, when sparkling wines or beers are 
indulged in; and when the carbonates of the alkalies, lime-water, and 
lemon-juice, are administered. It is deposited as a urinary sediment in 
the form of small, brilliant octohedra, having the appearance of the 
backs of square letter-envelopes, or in dumb-bells. It is usually deposited 
from acid urine, and accompanied by crystals of uric acid. Sometimes, 
however, it occurs in urines undergoing alkaline fermentation, in which 
case it is accompanied by crystals of ammonio-magnesian phosphate. 

The renal or vesical calculi of calcium oxalate, known as mulberry cal- 
culi, are dark brown or gray, very hard, occasionally smooth, generally 
tuberculated, soluble in hydrochloric acid without effervescence; and 
when ignited, they blacken, turn white, and leave an alkaline residue. 

Analytical characters. — Ammonium sulphydrate nothing, unless 
the calcium salt be the phosphate, oxalate, or fluoride in acid solution, 
when it forms a white precipitate. Alkaline carbonates, white precipi- 
tate, not prevented by the presence of ammoniacal salts. Ammonium 
oxalate, white precipitate, insoluble in acetic acid; soluble in hydro- 
chloric or nitric acid. Sulphuric acid, white precipitate, from solutions 
which are not too dilute; very sparingly soluble in water, insoluble in al- 
cohol; soluble in sodium hyposulphite solution. Sodium tungstate, 
dense white precipitate, even from dilute solutions. Colors the flame of 
the Bunsen burner reddish yellow. 



BARIUM. 
Ba 137.2 

The element itself is not of interest. 

Oxides. — Barium Monoxide — Baryta — BaO — is prepared, by calcin- 
ing the nitrate, as a grayish white caustic earth. It unites readily with 
water to form a hydrate, BaH 2 2 , whose aqueous solution is baryta water. 

Chloride — Barii chloridum (U. S.) — BaCl 2 + 2Aq. — is obtained by 
treating the native sulphide, or carbonate, with hydrochloric acid. It 
forms crystalline plates, permanent in air, soluble in water. 

Analytical characters. — Alkaline carbonates, white precipitate in 
alkaline solution. Sulphuric acid, or calcium sulphate, white precipi- 
tate, insoluble in acids. Sodium phosphate, white precipitate, soluble in 
nitric acid. Colors the Bunsen flame greenish yellow. 

Action on the economy. — The oxides and hydrate act as corro- 



416 GENERAL MEDICAL CHEMISTRY. 

sives by virtue of their alkalinity, and also as true poisons. All soluble 
compounds of barium, and those which are readily converted into soluble 
compounds in the stomach, are actively poisonous. Soluble sulphates, 
followed by emetics, are indicated as antidotes. 



IV. MAGNESIUM GROUP. 

Magnesium, Mg, 24; Zinc, Zn, 65.2; Cadmium, Cd, 112. 

Each of these elements forms a single oxide — a corresponding basic 
hydrate, and a series of salts in which its atoms are divalent. 

MAGNESIUM. 
Mg 24 

Is prepared by heating its chloride with sodium. It is a white metal; 
sp. gr. 1.75; fuses at 1000°; burns with great brilliancy in air; decom- 
poses vapor of water when heated; reduces carbon dioxide with the aid 
of heat; combines directly with chlorine, sulphur, phosphorus, arsenic, 
and nitrogen; dissolves in dilute acids, but is not affected by alkaline 
solutions. 

Oxide — Calcined magnesia — Magnesia (U. S., Br.) — MgO — is ob- 
tained by calcining the carbonate, hydrate, or nitrate. Is a light, bulky, 
white powder, odorless, and tasteless; has an alkaline reaction; almost in- 
soluble in water; dissolves readily in dilute acids without effervescence. 

Hydrate — Hydrated magnesia — MgH 2 2 — is formed when a solution 
of a magnesium salt is precipitated with sodium hydrate in excess, in the 
absence of ammoniacal salts. It exists in mixtures holding it in suspen- 
sion in water (milk of magnesia), used as antidotes to the effects of acid 
corrosives. 

Chloride, MgCl 2 — is obtained by dissolving the carbonate in hydro- 
chloric acid. It is one of the most deliquescent substances known, and 
imperfectly purified table-salt containing it, along with calcium chloride, 
becomes damp on exposure to air. 

Salts. — Sulphate — Epsom salt — Sedlitz salt — Magnesii sulphas (U. 
S.) — Magnesias sulphas (Br.) — S0 4 Mg+7Aq. — exists in solution in sea- 
water and in the waters of many mineral springs, especially in those belong- 
ing to the class of bitter waters. It is obtained artificially by the action of 
sulphuric acid upon magnesium carbonate. It crystallizes in rhombic 
needles; fuses and gradually loses water of cn^stallization up to 132°, 
when it retains 1 Aq., which is driven off at 210°. It dissolves in 0.8 
parts of water at 1 9°. 

Phosphates. — These phosphates resemble those of calcium in their 
constitution and properties, and accompany them in the situations in 
which they occur in the animal body, but in much smaller quantity. 

Magnesium also forms double phosphates, constituted by the substitu- 
tion of one atom of the divalent metal for two of the atoms of basic hy- 
drogen, of a molecule of phosphoric acid and of an atom of an alkaline 
metal, or of an ammonium group, for the remaining basic hydrogen. 



MAGNESIUM. 417 

One of these compounds is ammonio-magnesian phosphate ; triple phos- 
phate, P0 4 Mg(NH 4 ) + 6x\q. — which is formed when excess of an alkaline 
phosphate and of ammonia are added to a solution containing magnesium. 

In the urine, alkaline phosphates and magnesium salts are always 
present, and consequently when, by decomposition of urea, the urine be- 
comes alkaline, the conditions for the formation of this compound are 
fulfilled; and being practically insoluble, especially in the presence of 
excess of phosphates and of ammonia, it is deposited in crystals, usually 
tabular, sometimes feathery and stellate in form. When it is formed in 
the bladder, in the presence of some body to serve as a nucleus, the 
crystallization takes place upon the nucleus and a fusible calculus is 
produced. 

Silicates constitute a number of important minerals: talc, steatite or 
soapstone, asbestos, and meerschaum. 

Carbonates. — Magnesium carbonate — Neutral carbonate — C0 3 Mg — 
exists in magnesite, and, combined with calcium carbonate, in dolomite. 
It cannot be formed, like most other carbonates, by decomposing a 
magnesium salt with an alkaline carbonate, but may be produced by 
passing carbon dioxide through water holding tetramagnesic tricarbonate 
in suspension. Trimagnesic dicarbonate, 2(C0 3 Mg),MgH 2 O 2 + 2H 2 O — is 
formed in small crystals when a solution of magnesium sulphate is pre- 
cipitated with excess of sodium carbonate and the mixture boiled. Tetra- 
magnesic tricarbonate — Magnesia alba — Magnesii carbonas (U. S.) — ■ 
Magnesias carbonas (Br.) — 3(CO 3 Mg),MgH 2 O 2 +3H 2 — occurs in com- 
merce in the form of light, white cubes, composed of a powder which is 
amorphous or partly crystalline. It is prepared by precipitating a solu- 
tion of magnesium sulphate with one of sodium carbonate; if the pre- 
cipitation occur in cold dilute solutions {Magnesias carbonas Icevis, Br.), 
very little carbon dioxide is given off; a light, bulky precipitate falls, and 
the solution contains magnesium, probably in the form of the bicarbonate 
(C0 3 ) H 2 Mg. ; this solution, on standing, deposits crystals of the carbo- 
nate, C0 3 Mg + 3Aq. If hot concentrated solutions be used and the liquid 
then boiled upon the precipitate, carbon dioxide is given off, and a denser, 
heavier precipitate is formed, which varies in composition according to 
the length of time during which the boiling is continued, and to the pres- 
ence or absence of excess of sodium carbonate. The pharmaceutical pro- 
duct is intended to have the composition given above; it frequently con- 
tains 4(C0 3 Mg),MgH 2 O 2 + 4H 2 O, or even 2(C0 3 Mg),MgH 2 2 + 2H 2 O. 
All of these compounds are very sparingly soluble in water, but much 
more soluble in water containing ammoniacal salts. 

Analytical characters. — A.?nmonium hydrate, voluminous white 
precipitate from neutral solutions. Potassium or sodium hydrate, volu- 
minous white precipitate from warm solutions; prevented by the pres- 
ence of ammonium salts and of certain organic substances. Ammonium 
carbonate, slight precipitate from hot solutions; prevented by the pres- 
ence of ammoniacal salts. Sodium or potassium carbonate, white pre- 
cipitate, best from hot solution; prevented by the presence of ammoni- 
acal compounds. Disodic phosphate, white precipitate in hot, not too 
dilute solutions. Oxalic acid, nothing alone, but in the presence of am- 
monium hydrate a white precipitate; not formed in the presence of the 
salts or chloride of ammonium. 
27 



418 GENERAL MEDICAL CHEMISTRY. 

ZINC. 
Zn 65.2 

Is a bluish white metal ; either crystalline, granular, or fibrous. 
Pure zinc is quite malleable and ductile; the commercial is usually brit- 
tle; at 130° — 150° it is pliable; at 200° — 210° it again becomes brittle; 
it fuses at 415°, and distils at 1040°; sp. gr. 6.862 if cast, 7.215 if rolled; 
at 500° it burns with a greenish flame and gives off snowy flakes of the 
oxide (lana philosophica, pompholix). In moist air it becomes coated 
with a hydrocarbonate. Pure sulphuric acid, S0 4 H 2 , is not affected by 
pure zinc in the cold; the commercial metal dissolves in the diluted acid 
with evolution of hydrogen; the action is more rapid in the presence of 
copper or platinum, less so in that of mercury. It also decomposes nitric, 
hydrochloric, and acetic acids. 

When required in toxicological analysis, it must be free from arsenic, 
and, in some instances, from phosphorus. It is better to test samples 
until a pure one is found, than to attempt the purification of a contami- 
nated metal. 

Oxide — Zinci oxidum (U. S., Br.) — ZnO — is prepared either by cal- 
cining the precipitated carbonate, or by burning the metal in a current 
of air. An impure oxide, known as tutty, is deposited in the flues of 
zinc furnaces and irl those in which brass is fused. When obtained by 
calcination of the carbonate, it forms a soft, white, tasteless, and odorless 
powder; when produced by burning the metal, it occurs in light, volumi- 
nous, white masses. It is neither fusible, volatile, nor decomposable by 
heat, and is completely insoluble in neutral solvents. It dissolves in dilute 
acids, with formation of the corresponding salts. 

It is used in the arts as a white pigment in place of lead carbonate, 
and is not darkened by hydrogen sulphide. 

Zinc hydrate, ZnH 2 2 — cannot be obtained by union of the oxide 
with water, but is formed when a solution of a zinc salt is precipitated 
by potash. It is, when freshly precipitated, very soluble in alkalies and 
in solutions of ammoniacal salts. 

Chloride — Butter of zinc — Zinci chloridum (U. S., Br.) — ZnCl 2 + Aq. 
— is obtained by dissolving zinc in hydrochloric acid. It forms a soft, 
white mass; very deliquescent, fusible, and volatile; extremely soluble in 
water, freely soluble in alcohol; its solution has a burning, metallic 
taste, destroys vegetable tissues, dissolves silk, and exerts a strong, dehy- 
drating action upon organic substances in general. 

In dilute solution it is used as a disinfectant (Burnett's fluid), as a 
preservative of wood, and as an embalming injection. 

Salts. — Sulphate — White vitriol — Zinci sulphas (U. S., Br.) — S0 4 
Zn-j-wH 2 — is formed when zinc, or its oxide, sulphide, or carbonate is 
dissolved in dilute sulphuric acid. It crystallizes below 30°, with 7Aq.; 
at 30°, with 6 Aq. ; between 40° and 50°, with 5 Aq. ; at 0° from a con- 
centrated, acid solution, with 4Aq. ; with 2 Aq., as a crystalline powder 
deposited from a boiling solution by the addition of concentrated sul- 
phuric acid; with 1 Aq. from a saturated solution at 100°; finally, anhy- 
drous, by heating the preceding to 238°. 

The salt usually met with is that with 7 Aq., which is very soluble in 
water; insoluble in absolute alcohol, sparingly soluble in weak alcohol. 



ZLNO. 419 

Its solutions have a strong, styptic taste; coagulate albumin when added 
in moderate quantity, the coagulum dissolving in an excess, and form 
insoluble precipitates with the tannins. 

Analytical characters. — Hydrate of potassium ■, sodium, or ammo- 
nium — white precipitate, soluble in excess. Potassium, or sodium car- 
bonate, white precipitate in the absence of ammoniacal salts. Hydrogen 
sulphide, in neutral solution, white precipitate; in presence of an excess 
of a mineral acid, this precipitation is prevented unless sodium acetate is 
also present. Ammonium sulphydrate, white precipitate, insoluble in 
excess, in potassium or ammonium hydrate, or in acetic acid; soluble in 
dilute mineral acids. Ammonium carbonate, white precipitate, soluble 
in excess. Disodic phosphate, in the absence of ammoniacal salts, white 
precipitate, soluble in acids or alkalies. Potassium ferrocyanide, white 
precipitate, insoluble in hydrochloric acid. 

Action on the economy. — All the compounds of zinc which are 
soluble in the digestive fluids behave as true poisons; and solutions of the 
chloride (in common use by tinsmiths, and in disinfecting fluids) have also 
well-marked corrosive properties. When zinc compounds are taken, it 
is almost invariably by mistake for other substances: the sulphate for 
Epsom salt, and solutions of the chloride for various liquids, gin, fluid 
magnesia, vinegar, etc. 

Metallic zinc is dissolved by solutions containing sodium chloride, or 
organic acids, for which reason articles of food kept in vessels of galvan- 
ized iron become contaminated with zinc compounds, and, if eaten, pro- 
duce, more or less intense symptoms of intoxication. For the same rea- 
son materials intended for analysis, in cases of supposed poisoning, should 
never be packed in jars closed by zinc caps. 



V. NICKEL GROUP. 
Nickel, Ni, 59; Cobalt, Co, 59. 

These two elements bear a certain resemblance to those of the iron 
group; from which they differ in forming, so far as known, no compounds 
similar to the ferrates, chromates, and manganates. They form com- 
pounds corresponding to the sesquioxide of iron, but the salts correspond- 
ing to the ferric series are wanting, or exceedingly unstable if they exist. 

Analytical characters. — Nickel — Ammonium sulphydrate, black 
precipitate, insoluble in excess. Potassium, or sodium hydrate, apple- 
green precipitate in the absence of tartaric acid; insoluble in excess. 
Ammonium hydrate, apple-green precipitate, soluble in excess; this solu- 
tion is violet and deposits the hydrate when heated with potash. 

Cobalt. — Ammonium sulphydrate, brown-black precipitate, insoluble 
in excess. Potash, blue precipitate, turns red slowly in the cold; quickly 
if heated; not formed in the cold in the presence of ammoniacal salts. 
Ammonium hydrate, blue precipitate; turns red in the absence of air, 
green in its presence. 



420 GENERAL MEDICAL CHEMISTRY. 

VI. COPPER GROUP. 
Copper, Cu, 63.5; Mercury, Hg, 200. 
Each of these elements forms two series of compounds; one of which 
contains the divalent group! / I" or (Hg )" and is designated by the 

Vcu/y 

termination ous / the other contains the single, divalent atoms, and is 
designated by the termination ic. 

COPPER 
Cuprum Cu 63.5 

A yellowish red metal, dark brown when finely divided; sp. gr. 8.914 
— 8.952; very malleable, ductile, and tenacious; a good conductor of 
heat and of electricity. It is unaltered in dry air; in damp air it is coated 
with a green basic carbonate; heated to redness in air, it is oxidized. Hot 
sulphuric acid dissolves it with liberation of sulphur dioxide; nitric acid, 
with liberation of nitrogen dioxide; and hot hydrochloric acid, with libera- 
tion of hydrogen. Weak acids form soluble salts with it in presence of 
air and moisture. Ammonium hydrate is colored blue by contact of air 
and copper. 

Oxides. — Cuprous oxide — Suboxide or black oxide — (Cu 2 )0 — is 
formed as a red or yellow powder, by calcining a mixture of cuprous chlo- 
ride and sodium carbonate. 

A yellow hydrate is precipitated when cupric salts are decomposed by 
boiling with glucose (Fehling's and Trommer's tests). It loses its water 
of hydration at 360°. 

Cupric oxide — Pinoxide — Black oxide — CuO — is prepared by heat- 
ing copper to dull redness in a current of air, or by calcining its nitrate. 
It is also formed by the precipitation of a boiling solution of a cupric 
salt by potash, and prolonged boiling of the liquid on the precipitate. 

It is black, or dark reddish brown, amorphous, and is reduced by char- 
coal, hydrogen, sodium, or potassium, at comparatively low temperatures. 
When heated in the presence of organic substances, it gives up its oxy- 
gen, converting the carbon of the organic body into carbon dioxide, and 
its hydrogen into water. It dissolves in acids with formation of salts. 

Sulphides. — Cuprous sulphide — Subsulphide or Protosulphide — 
Cu 2 S — occurs in nature in soft, fusible, gray crystals (chalcosine or copper 
glance), and in many double sulphides, among which is a double sulphide 
of copper and iron, known as copper i^y rites. 

Cupric sulphide — Protosulphide — CuS — is obtained by treating a 
solution of a cupric salt with hydrogen sulphide or ammonium suJphydrate. 
It is almost black when moist, greenish brown when dry. Hot nitric 
acid oxidizes it to cupric sulphate; hot hydrochloric acid converts it into 
cupric chloride, with separation of sulphur and formation of hydrogen sul- 
phide. It is sparingly soluble in ammonium sulphydrate, its solubility 
being increased by the presence of organic matter. 

Chlorides. — Cuprous chloride — Subchloride or Protochloride — Cu, 
Cl 3 — is prepared by heating copper with one of the chlorides of mercury; 



COPPER. 421 

by dissolving cuprous oxide in hydrochloric acid without contact of air; 
or by the action of reducing agents upon solutions of cupric chloride. It 
is a heavy, white powder; turns violet and blue by exposure to light; 
soluble in concentrated hydrochloric acid, insoluble in water. It forms a 
crystallizable compound with carbon monoxide, and its solution in hydro- 
chloric acid is used in analysis to absorb that gas. 

Cupric chloride — Chloride or Deutochloride — CuCl 2 — is formed by 
dissolving copper in aqua regia; if copper be present in excess, it reduces 
the cupric to cuprous chloride. It crystallizes in bluish green, rhombic 
prisms with 2 Aq., deliquescent, very soluble in water and in alcohol. 

Salts. — Nitrates. — Cuprous nitrate is unknown. Cupric nitrate, 
(N0 3 ) 2 Cu — is formed by dissolving copper, or its oxide, or carbonate in 
nitric acid. It crystallizes at 20° to 25° with 3 Aq. ; below 20° with 
6 Aq. 

Sulphates. — The existence of cuprous sulphate is doubtful. Cuprie 
sulphate — Sulphate of copper — Blue vitriol — Bluestone — Cupri sulphas 
(U. S., Br.) — S0 4 Cu-(-5Aq. — is prepared: 1st, by roasting copper py- 
rites; 2d, from the water of copper-mines; 3d, by exposing copper, moist- 
ened with dilute sulphuric acid, to air; 4th, by heating copper with con- 
centrated sulphuric acid. 

As ordinarily crystallized, it is in fine, blue, oblique prisms, which 
require for their solution 2.71 parts of water at 19°; and 0.55 parts at 
100°. Insoluble in alcohol. The crystals effloresce in dry air at 15°, losing 
2 Aq. ; at 100° they still retain 1 Aq., which they lose at 230°, forming 
a white, amorphous powder. The anhydrous salt, in taking up water, re- 
sumes its blue color. Its solutions are blue, acid, styptic, and metallic in 
taste. 

When ammonium hydrate is added to a solution of cupric sulphate, 
a bluish white precipitate falls, which redissolves in excess of the alkali, 
to form a deep blue solution; strong alcohol floated over the surface of 
this solution separates long, right rhombic prisms, having the composi- 
tion S0 4 Cu,4NH 3 + H 2 0, which are very soluble in water; their solution 
constitutes ammonio-sulphate of copper or aqua sapphirina; and they 
exist, mixed with other substances, in the cuprum ammo?iiatum (U. S.). 

Arsenite — ScheeWs green — Mineral green — is a mixture of cuprie 
arsenite and hydrate; prepared by adding potassium arsenite to solution 
of cupric sulphate. It is a grass-green powder, insoluble in water; solu- 
ble in ammonium hydrate, or in acids. Exceedingly poisonous. 

Schweinfurt green — Mitis green or Paris green — is the most fre- 
quently used, and the most dangerous of the cupro-arsenical pigments. 
It is prepared by adding a thin paste of neutral cupric acetate with water 
to a boiling solution of arsenious acid, and continuing the boiling during 
a further addition of acetic acid. It is an insoluble, green, crystalline 
powder, having the composition (C 2 H 3 2 ) 2 Cu-{-3(As 2 4 Cu). It is decom- 
posed by prolonged boiling in water, by aqueous solutions of the alkalies, 
and by the mineral acids. 

Carbonates. — The existence of cuprous carbonate is doubtful. Cu- 
pric carbonate — C0 3 Cu — exists in nature, but has not been obtained arti- 
ficially. JDicupric carbonate — C0 3 Cu,CuH 2 2 — exists in nature as mala- 
chite. When a solution of a cupric salt is decomposed by an alkaline 
carbonate, a bluish precipitate, having the composition C0 3 Cu,CuH 2 O, 
4-H 2 0, is formed, which, on drying, loses H 2 0, and becomes green; it is 
used as a pigment under the name mineral green. Tricupric carbonate — - 
Sesquicarbonate of copper — 2(C0 3 Cu),CuH a 3 — exists in nature as a blue 



422 GENEKAL MEDICAL CHEMISTKY. 

mineral called azurite or mountain blue, and is prepared by a secret pro- 
cess for use as a pigment known as blue ash. 

Acetates. — Cupric acetate — Diacetate — Crystals of Venus — (C H 
2 ) 2 Cu + Aq. — is formed when cupric oxide or verdigris is dissolved in 
acetic acid; or by decomposition of solution of cupric sulphate by lead ace- 
tate. It crystallizes in large, bluish green prisms, with 1 Aq., which they 
lose at 140°; when heated to 240° or 260° they are decomposed, with 
liberation of glacial acetic acid. 

JBasic acetates. — Verdigris — Cupri subacetas (U. S.) — is a substance 
prepared by exposing to air piles composed of alternate layers of grape- 
skins and plates of copper, and removing the bluish green coating from the 
copper. It is a mixture, in varying proportions, of three different sub- 
stances: (C 2 H 3 o ) 2 Cu,CuH 2 2 + 5Aq.; [(0 2 H 3 2 ) 2 CuJ 2 ,CuH 2 O 2 + 5Aq.; 
and (C 2 H 3 2 ) 2 Cu;2(CuH 2 2 ). 

Analytical characters. — Cuprous — are very unstable and readily 
converted into cupric compounds. Potash, white precipitate, turnino- 
brownish. Ammonium hydrate, in absence of air, a colorless liquid; 
turns blue on exposure to air. 

Cupeic. — White when anhydrous; when soluble in water they form 
blue or green acid solutions. Hydrogen sulphide, black precipitate, 
insoluble in potassium or sodium sulphide, sparingly soluble in ammonium 
sulphydrate; soluble in hot concentrated nitric acid and in potassium 
cyanide. Alkaline sulphides, same as hydrogen sulphide. Potassium or 
sodium hydrate, pale blue precipitate, insoluble in excess. If the solution 
be heated over the precipitate, the latter contracts and turns black. Am- 
monium hydrate, in very small quantity, pale blue precipitate; with larger 
quantities a deep blue liquid. Potassium or sodium carbonate, greenish 
blue precipitate, insoluble in excess, and turning black when the liquid is 
boiled. Ammonium carbonate, pale blue precipitate, soluble with deep 
blue color in excess. Potassium cyanide, greenish yellow precipitate, 
soluble in excess. Potassium ferrocyanide, chestnut-brown precipitate, 
insoluble in weak acids, decolorized by potash. Iron is coated with 
metallic copper. 

Action on the economy. — The opinion, until recently universal 
among toxicologists, that all the compounds of copper are poisonous, has 
been much modified by recent researches. Certain of the copper com- 
pounds, such as the sulphate, having a tendency to combine with albu- 
minoid and other animal substances, produce symptoms of irritation by 
their direct local action when brought in contact with the gastric or in- 
testinal mucous membrane. One of the characteristic symptoms of such 
irritation is the vomiting of a greenish matter, which develops a blue 
color upon the addition of ammonium hydrate. 

Cases are not wanting in which severe illness, and even death, has 
followed the use of food which has been in contact with imperfectly 
tinned copper vessels; cases in which nervous and other symptoms re- 
ferable to a truly poisonous action have occurred. As, however, it has 
also been shown that non-irritant, pure copper compounds may be taken 
in considerable doses with impunity, it appears at least probable that the 
poisonous action attributed to copper is due to other substances. The 
tin and solder used in the manufacture of copper utensils contain lead, 
and in some cases of so-called copper-poisoning, the symptoms have been 
such as are as consistent with lead-poisoning as with copper-poisoning. 
Copper is also notoriously liable to contamination with arsenic, and it is 
by no means improbable that compounds of that element are the active 



MERCURY. 423 

poisonous agents in some cases of supposed copper-intoxication. Nor is 
it improbable that articles of food allowed to remain exposed to air in 
copper vessels should undergo those peculiar changes which result in the 
formation of poisonous substances, such us the sausage- or cheese-poisons, 
or the ptoamines. 

The treatment, when irritant copper compounds have been taken, 
should consist in the administration of white of egg or of milk, with 
whose albuminoids an inert compound is formed by the copper salt. If 
vomiting do not occur spontaneously, it should be induced by the usual 
methods. 

The detection of copper in the viscera after death is not without 
interest, especially if arsenic have been found, in which case its discovery 
or non-discovery enables us to differentiate between poisoning by the ar- 
senical greens and that by other arsenical compounds. The detection of 
mere traces of copper is of no significance, because, although copper is 
not a physiological constituent of the body, it is almost invariably pres- 
ent, having been taken with the food. 

Pickles and canned vegetables are sometimes intentionally greened by 
the addition of copper ; this fraud is readily detected by inserting a large 
needle into the pickle or other vegetable ; if copper be present the steel 
will be found to be coated with copper after half an hour's contact. 



MERCURY. 

Hydrargyrum Hg 200 

Commercial mercury is contaminated with other metals. It may be 
purified by shaking the distilled metal with mercurous nitrate solution, 
and preserving it under that liquid or strong nitric acid. 

It is a bright, metallic liquid; crystallizes at — 40°; boils at 360° 
(350° of the air thermometer); volatilizes slightly at all temperatures 
above — 7°; sp. gr. 13.596. It forms alloys, called amalgams, with most 
other metals; it does not attack iron, and only amalgamates with platinum 
when heated. If pure, it is not altered in air at the ordinary tempera- 
ture, but, if impure, is coated with a gray film of mercuric oxide; heated 
in air to near its boiling point, it is oxidized. It does not decompose 
water. It combines directly with chlorine, bromine, iodine, and sulphur. 
Hot, concentrated sulphuric acid dissolves it with evolution of sulphur 
dioxide, and formation of mercuric sulphate. Nitric acid dissolves it in 
the cold with formation of a nitrate. 

Hydrargyrum cum creta (U. S., Br.) and TInguentum hydrargyri 
(U. S., Br.) — owe their activity to small quantities of mercurous oxide, 
formed during their preparation; the cause of the greater activity of the 
latter preparation being due to a more extensive oxidation. It is also 
probable that the absorption of vapor of mercury by cutaneous surfaces 
is preceded by its conversion into mercuric chloride. 

Oxides. — Mercurous Oxide — Protoxide or black oxide — Hg Q — is 
obtained by adding a solution of mercurous nitrate to an excess of solu- 
tion of potassium hydrate. It is a brownish black, tasteless powder; 
very prone to decomposition into mercuric oxide and mercury. Hydro- 
chloric acid converts it into mercurous chloride, and other acids into the 
corresponding mercurous salts. 



424 GENERAL MEDICAL CHEMISTRY. 

It is also formed by the action of calcium hydrate "upon mercurous 
compounds, and exists in the Lotio hydrargyri nigra (Br.) or black 
wash. 

Mercuric Oxide — Med or binoxide — Hydrargyri oxidum flavum 
(U. S., Br.) — Hydrargyri oxidum rubrum (U. S., Br.) — HgO — is pre- 
pared by calcining mercuric nitrate as long as brown fumes are given 
off; or by precipitating a solution of a mercuric salt by excess of potas- 
sium hydrate. The products obtained by these methods, although the 
same in composition, differ from each other in their physical properties 
and in the activity of their chemical actions. That obtained by the cal- 
cination of the nitrate, Hydr. oxid. rubrum, is red and crystalline in 
structure; that obtained by precipitation, Hydr. oxid. flavum, is yellow 
and amorphous. The latter is much the more active in its chemical and 
medicinal actions. 

Mercuric oxide is very sparingly soluble in water, the solution having 
a metallic taste and an alkaline reaction. It exists both in solution and 
in suspension in the Lotio hydrargyri flava (Br.) or yelloio wash, pre- 
pared by the action of lime water upon a mercuric salt. 

When exposed to air and light it turns black, more rapidly in the 
presence of organic matter, giving off oxygen and liberating mercury. It 
is an active oxidizing agent. It decomposes the chlorides of many 
metallic elements in solution, with formation of a metallic oxide and of 
mercuric oxychloride; combines with the alkaline chlorides to form soluble 
double chlorides, chloromercurates or chlorhydrar gyrates / and forms 
similar compounds with the alkaline iodides and bromides. 

Sulphides. — Mercurous sulphide — Hg 2 S — a very unstable com- 
pound, formed by the action of hydrogen sulphide upon mercurous salts. 

Mercuric sulphide — Red sulphide — Cinnabar — Vermilion — Hy- 
drargyri sulphuretum rubrum (U. S.) — HgS — exists in nature in amor- 
phous red masses or in red crystals, and is the chief ore of mercury. If 
sulphur and mercury be ground up together in the cold, or if a solution 
of a mercuric salt be decomposed by hydrogen sulphide, a black sulphide 
is formed, which is the JEthiops mineralis of the older pharmacists. 

A red sulphide is obtained in the arts for use as a pigment {vermil- 
ion), by agitating for some hours at 60° a mixture of mercury, sulphur, 
potash, and water. It is a fine, red powder, which turns brown, and finally 
black, when heated. Heated in air it burns with formation of sulphur 
dioxide and volatilization of mercury. It is decomposed by strong sul- 
phuric acid, but not by nitric or hydrochloric 'acids. 

Chlorides. — Mercurous chloride — Protochloride — Mild chloride — 
Calomel — Hydrargyri chloridum mite (U.S.) — Hydrargyri subchlori- 
dum (Br.) — Iig 2 Cl 2 — is now principally obtained by the mutual decompo- 
sition of sodium chloride and mercurous sulphate. Mercuric sulphate is 
obtained by heating together 2 parts of mercury and 3 parts of sulphuric 
acid; this is then caused to combine with an equal amount of mercury to 
that first used, to form mercurous sulphate; which is mixed with dried 
sodium chloride, and the mixture heated in glass vessels, connected with 
condensing chambers. 

In practice, varying quantities of mercuric chloride are also formed, 
and must be removed from the product by washing with boiled, distilled 
water until the washings no longer precipitate with ammonium hydrate. 
The presence of mercuric chloride in calomel may be detected by the for- 
mation of a black stain upon a bright iron surface, immersed in the cal- 
omel, moistened with alcohol; or by the production of a black color by 



MERCURY. 425 

hydrogen sulphide in water which has been in contact with and filtered 
from calomel so contaminated. 

Calomel is also formed in a number of other reactions: 1st, by the ac- 
tion of chlorine upon excess of mercury; 2d, by the action of mercury 
upon ferric chloride; 3d, by the action of hydrochloric acid, or of a 
chloride, upon mercurous oxide, or upon a mercurous salt; 4th, by the 
action of reducing agents, including mercury, upon mercuric chloride. 

Calomel crystallizes in nature, and when sublimed, in quadratic 
prisms; when precipitated it is deposited as a heavy, amorphous, white 
powder, faintly yellowish, and producing a yellowish mark when rubbed 
upon a dark suface. It sublimes, without fusing, between 420° and 
500°; is insoluble in cold water and in alcohol; soluble in boiling water 
to the extent of 1 part in 12,000; when boiled with water for some time, 
it suffers partial decomposition, mercury is deposited and mercuric chlor- 
ide dissolves. 

When exposed to light, calomel becomes yellow, then gray, owing to 
partial decomposition, with liberation of mercury and formation of mer- 
curic chloride. Chlorine and aqua regia readily convert it into mercuric 
chloride. Iodine, in the presence of water, converts it into a mixture of 
mercuric iodide and chloride. Hydrochloric acid and alkaline chlorides 
convert it into mercuric chloride. This change occurs in the stomach 
when calomel is taken internally, and that to such an extent when large 
quantities of chlorides are taken with the food, that calomel cannot be 
used in naval practice as it may be with patients who do not subsist upon 
salt provisions. Potassium iodide converts it into mercurous iodide, 
which is then decomposed, by an excess of alkaline iodide, into mercuric 
iodide, which dissolves, and mercury. . Solutions of the sulphates of so- 
dium, potassium, and ammonium dissolve notable quantities of calomel. 

The hydrates and carbonates of sodium and potassium decompose 
it with formation of mercurous oxide, which is decomposed into mercuric 
oxide and mercury; if alkaline chlorides be also present, they react upon 
the mercuric oxide, thus produced, with formation of mercuric chloride. 

Mercuric Chloride — Perchloride or bichloride — Corrosive sublimate 
— Hydrargyri chloridum corrosivum (U. S.) — Hydrargyri perchloridum 
(Br.) — HgCl 2 — is prepared by heating a mixture of 5 parts of dry mer- 
curic sulphate with 5 parts of dry sodium chloride and 1 part of manga- 
nese dioxide in a glass vessel communicating with a condensing chamber. 

It crystallizes by sublimation in rectangular octahedra, and by 
evaporation of its solutions in flattened, right rhombic prisms; fuses at 
about 265°, and boils at about 295°; 100 parts of water dissolve 6.57 
parts of mercuric chloride at 10°, and 53.96 parts at 100°; cold alcohol 
dissolves it to the extent of 40 per cent, of its weight. It is also soluble 
in ether, and very soluble in hot hydrochloric acid, which latter solution 
gelatinizes on cooling. Its solutions have a disagreeable, acid, styptic 
taste, and are highly poisonous. 

It is easily reduced to calomel and elementary mercury, and its aque- 
ous solutions are so decomposed when exposed to light, a change which 
is retarded by the presence of sodium chloride. When heated with mer- 
cury it is converted into mercurous chloride. Zinc, cadmium, nickel, iron, 
lead, copper, and bismuth remove a part or all of its chlorine, with separa- 
tion of calomel or of mercury, when they are heated with dry mercuric 
chloride or with its solution. Hydrogen sulphide decomposes it with 
separation of a yellow sulpho-chloride, which, with an excess of the gas, is 
converted into the black mercuric sulphide. It is soluble without decom- 



426 GENERAL MEDICAL CHEMISTRY. 

position in sulphuric, nitric, and hydrochloric acids. Hydrates of sodium 
and potassium decompose it, with separation of a reddish brown oxychlo- 
ride if added in sufficient quantity, or of the orange-colored mercuric ox- 
ide if an excess of the precipitant be used. The hydrates of calcium and 
magnesium effect a similar decomposition, which does not, however, take 
place in the presence of an alkaline chloride or of certain organic matters, 
such as sugar and gum. Many organic substances decompose it into 
calomel and mercury, especially under the influence of sunlight. Albu- 
men forms with it a white precipitate, which is insoluble in water, but 
soluble in an excess of fluid albumen and in solutions of alkaline chlorides. 
It readily combines with metallic chlorides to form soluble double salts, 
or chloromer curates. One of these, obtained in flattened, rhombic prisms 
by the cooling of a boiling solution of mercuric chloride and ammonium 
chloride, has the composition HgCl,,,2(NH 4 01) + Aq., and was formerly 
known as sal alembroth or sal sapiential. 

. Mercurammonium chloride — Mercury chloramidide — Infusible 
white precipitate — Ammoniated mercury — Hydrargyrum ammoniaticm 
(U. S., Br.) — NH 2 HgCl — is prepared by adding a slight excess of ammo- 
nium hydrate solution to a solution of mercuric chloride. It is a white 
powder, insoluble in alcohol, ether, and cold water; decomposed by hot 
water with separation of a heavy, yellow powder. It is entirely volatile 
without fusion. The fusible white precipitate is formed in small crystals 
when a solution containing equal parts of mercuric chloride and ammo- 
nium chloride is decomposed by sodium carbonate. It is mercurdiammo- 
nium chloride, NH 3 HgCl,NH 4 Cl. 

Iodides. — Mercurous iodide — Protoiodide or yellow iodide — Hy- 
drargyri iodidum viride (U. S., Br) — Hg 2 I 2 — is prepared by grinding 
together 200 parts of murcury and 127 parts of iodine with a little alco- 
hol until a green paste is formed. It is a greenish yellow, amorphous 
powder, insoluble in water and in alcohol. When heated it turns brown 
and volatilizes completely. When exposed to light, or even after a time 
in the dark, it is decomposed into mercuric iodide and mercury. The 
same decomposition is brought about instantly by potassium iodide; more 
slowly by solutions of alkaline chlorides and by hydrochloric acid when 
heated. Ammonium hydrate dissolves it with separation of a gray pre- 
cipitate. 

Mercuric iodide — JBiniodide or red iodide — Hydrargyri iodidum 
rubrum (U. S., Br.) — Hgl 2 — is obtained by double decomposition between 
mercuric chloride and potassium iodide, care being had to avoid too great 
an excess of the alkaline iodide, that the soluble potassium iodhydrargy- 
rate may not be formed. 

It is sparingly soluble in water; with alcohol forms colorless solutions. 
It dissolves readily in many dilute acids and in solutions of ammoniacal 
salts, alkaline chlorides, and mercuric salts; and in solutions of alkaline 
iodides. Iron and copper convert it into mercurous iodide, then into mer- 
cury. The hydrates of potassium and sodium decompose it into oxide or 
oxyiodide, and combine with another portion to form iodhydrargy rates, 
which dissolve. Ammonium hydrate separates from its solution a brown 
powder, and forms a yellow solution which deposits white flocks. 

Cyanides. — Mercuric cyanide — Hydrargyri cyanidum (U. S.) — 
Hg(CN) 2 — is best prepared by heating together, for a quarter of an hour, 
potassium ferrocyanide, 1 part; mercuric sulphate, 2 parts; and water 8 
parts. It crystallizes in quadrangular prisms; soluble in 8 parts of cold 
water, much less soluble in alcohol; highly poisonous. When heated dry 



MERCURY. 427 

it blackens, and is decomposed into cyanogen and mercury; if heated in 
the presence of moisture it yields hydrocyanic acid, mercury, carbon di- 
oxide, and ammonia. Hot, concentrated sulphuric acid, and hydrochloric, 
hydrobromic, hydriodic, and sulphydric acids in the cold, decompose it 
with liberation of hydrocyanic acid. It is not decomposed by alkalies. 

Salts. — Nitrates. — There exist, beside the normal mercurous and mer- 
curic nitrates, (N0 3 ) 2 (Hg 2 ) and (N0 3 ) 2 Hg, three basic mercurous nitrates, 
three basic mercuric nitrates, and a mercuroso-mercuric nitrate. 

Mercurous nitrate — (N0 3 ) 2 (Hg 2 ) + 2 Aq. — is formed when excess of 
mercury is digested with nitric acid, diluted with one-half vol. of water, 
until short, prismatic crystals separate. 

It effloresces in air; fuses at 70°; dissolves in a small quantity of hot 
water, but with a larger quantity is decomposed with separation of a 
yellow basic trimercuric nitrate, (N0 3 ) 2 Hg,2HgO + Aq. 

The dimercurous nitrate — (N0 3 ) 2 (Hg 2 ),Hg 2 + Aq. — is formed by act- 
ing upon the preceding salt with cold water until it turns lemon-yellow; 
or by extracting with cold water the residue of evaporation of the pro- 
duct obtained by acting upon excess of mercury with concentrated nitric 
acid. 

A trimercurous nitrate — (N0 3 ) 4 (Hg 2 ) 2 ,Hg 2 + 3Aq. — is obtained in 
large, rhombic prisms, when excess of mercury is boiled with nitric acid, 
diluted with 5 parts of water, for five to six hours, the loss by evaporation 
being made up from time to time. 

Mercuric nitrate — (N0 3 ) 2 Hg — is formed when mercury or mercuric 
oxide is dissolved in excess of nitric acid, and the solution evaporated at a 
gentle heat. A sirupy liquid is obtained, which, over quick-lime, deposits 
large, deliquescent crystals, having the composition 2[(N0 3 ) 2 Hg]-j-Aq., 
while there remains an uncrystallizable liquid, (N0 3 ) 2 Hg-}-2Aq. 

This salt is soluble in water and exists in the Liq. hydrargyri nitratis 
(U. S.) or Liq. hydrargyri nitratis acidus (Br.); in the volumetric stan- 
dard solution used in Liebig's process for urea; and probably in citrine 
ointment, Unguentum hydrargyri nitratis (U. S., Br.). 

Dimercuric nitrate — (N0 3 ) 2 Hg,HgO + Aq. — is formed when mercuric 
oxide is dissolved to saturation in hot nitric acid, diluted with its volume 
of water. It crystallizes on cooling in needles; is decomposed by water 
into trimercuric nitrate, (N0 3 ) 2 Hg.2HgO, and neutral mercuric nitrate. 

A hexamercuric nitrate — (N0 3 )„Hg,5HgO — is also formed, as a red 
powder, by the action of water upon trimercuric nitrate. 

Sulphates. — Mercurous and Mercuric Sulphates — S0 4 (Hg 2 ) and 
S0 4 TIg — are crystalline compounds, which are formed as a step in the 
preparation of mercurous and mercuric chlorides (q. v.). 

Analytical characters. — Mercurous. — Hydrochloric acid, white 
precipitate, insoluble in water and in acids, except aqua regia; turns 
black on the addition of ammonium hydrate; when boiled with hydro- 
chloric acid, deposits mercury, while mercuric chloride dissolves. Hydro- 
gen sulphide, black precipitate, insoluble in alkaline sulphides, in dilute 
acids, and in potassium cyanide; partly soluble in boiling nitric acid. 
Potassium hydrate, black precipitate, insoluble in excess. Potassium 
iodide, greenish precipitate, converted by excess into mercury, which 
remains, and mercuric iodide, which dissolves. 

Mercuric. — Hydrogen sulphide, black precipitate. If the reagent 
be slowly added, the precipitate is first white, then orange, finally black. 
A.mmonium sulphydrate, black precipitate, insoluble in excess, except in 
the presence of organic matter. Potassium or sodium hydrate, yellow 



428 GENERAL MEDICAL CHEMISTRY. 

precipitate, insoluble in excess. Ammonium hydrate, white precipitate, 
soluble in great excess, and in solutions of ammoniacal salts. Potassium, 
carbonate, red precipitate. Potassium iodide, yellow precipitate, rapidly- 
turning to salmon-colored, then to red; readily soluble in excess of pre- 
cipitant or in great excess of mercuric salt. 

Action on the economy. — Mercury, in the metallic form, is without 
action upon the animal economy so long as it remains such; on contact, 
however, witfh alkaline chlorides it is converted into a soluble double 
chloride, and this the more readily the greater the degree of subdivision 
of the metal. The mercurials insoluble in dilute hydrochloric acid are 
also inert until they are converted into soluble compounds. 

Mercuric chloride, a substance into which many other compounds of 
mercury are converted when taken into the stomach or applied to the 
skin, not only has a distinctly corrosive action, by virtue of its tendency 
to unite with albuminoids, but when absorbed it produces well-marked 
poisonous effects, somewhat similar to those of arsenical poisoning; 
indeed, owing to its corrosive action and to its greater solubility, and 
more rapid absorption, it is a more dangerous poison than arsenic triox- 
ide. In poisoning by corrosive sublimate, the symptoms begin sooner after 
the ingestion of the poison than in arsenical poisoning, and those phe- 
monena referable to the local action of the toxic are more intense. 

The treatment should consist in the administration of white of eg,g, 
not in too great quantity, and the removal of the compound formed, by 
emesis, before it has had time to redissolve in the alkaline chlorides con- 
tained in the stomach. 

Absorbed mercury tends to remain in the system in combination with 
albuminoids, from which it may be set free, or, more properly, brought 
into soluble combination, at a period quite removed from the date of last 
administration, by the administration of alkaline iodides. 

Mercury is eliminated principally by the saliva and urine, in which it 
may be readily detected. The fluid is faintly acidulated with hydro- 
chloric acid, and in it is immersed a short bar of zinc, around which a 
spiral of dentist's gold- foil is wound in such a way as to expose alternate 
surfaces of zinc and gold. After 24 hours, if the saliva or urine contain 
mercury, the gold will be whitened by amalgamation; and, if dried and 
heated in the closed end of a small glass tube, will give off mercury, 
which condenses in globules, visible with the aid of a magnifier, in the 
cold part of the tube. 



WEIGHTS AND MEASURES. 429 



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INDEX. 



ACENAPHTHALENE, 337 

Aceta, 187 

Acetamide, 208 

Acetone. 204 

Acetones, 154 

Acetyl hydrate, 185 
hvdride, 200 
methylide, 204 

Acetylene, 287 

Acid, acetic, 185 
aconitic, 291 
acrylic, 224 
adipic, 253 
allantoic, 272 
allanturic, 272 
arnalic, 355 
amidoacetic, 208 
amidobutyric, 214 
arnido apioic, 214 
amidopropionic, 214 
amidovalerianic, 214 
amyl sulphuric, 199 
angelic, 225 
arachaic, 280 
arachic, 193 
arsenic, 121, 125 
arsenious, 118, 121 
aspartic, 277 
auric, 374 
azelaic, 254 
benic, 193 
benostearic, 193 
benzoic, 297, 326 
benzoglycolic, 327 
binitrobenzoic, 327 
bismuthic, 389 
boracic, 140 
boric, 140 
bromic, 78 
butvlformic, 191 
butyric, 189 
cachoutannic, 345 
caffeic, 345 
caffetannic, 345 
camphic, 296 
campholic, 296 
capric, 192 
caproic, 191 



Acid, caprylic, 192 
carbamic, 274 
carbolic, 320 
carbonic, 234 
carminic, 342 
cathartic, 342 
cerotic, 193 
chenocholic, 212 
chenotaurocholic, 212 
chloric, 76 
chlorous, 76 
cholalic, 212 
choleic, 211 
cholesteric, 385 
cholic, 210, 212 
cholonic, 211 
chromic, 375 
cinnamic, 297, 336 
citraconic, 291 
citric, 291 
cocinic, 280 
cocostearic, 280 
cresylic, 322 
crotonic, 225 
cyanic, 341 
cyanuric, 258 
decylic, 192 
delphinic, 191 
deoxyglutanic, 253 
dextro tartaric, 290 
dichloracetic, 187 
dichromic, 375 
digallic, 345 
digitallic, 343 
dilactic, 249 
disulphanilic, 333 
disulphuric, 92 
ditartaric, 291 
dithionic, 92 
elaidic, 226 
erythroglucic, 289 
ethalic, 193 
ethyldiacetic, 204 
ethylenolactic, 247 
ethyloxalic, 198 
ethyl sulphuric, 196 
fluoric, 70 
formic, 184 



432 



INDEX. 



Acid, gadinic, 283 
gallic, 320 
gallotannic, 344 
glucic, 300 

glycerophosphoric, 286 
glycocholic, 210 
glycolamic, 208 
glycolic, 246 
hemimellitic, 329 
hemipinic, 352 
heptylic, 192 
hexylic, 191 
hippuric, 327 
hyaenic, 193 
hydrobromic, 77 
hydrochloric, 72 
hydrocyanic, 339 
hydroferricyanic, 342 
hydroferrocyanic, 342 
hydrofluoric, 69 
hy droll uosilicic, 372 
hydriodic, 80 
hydromellitic, 330 
hydrosulphuric, 84 
hydrosulphurous, 88 
hydurilic, 268 
hyocholic, 212 
hyoglycocholic, 212 
hyotaurocholic, 212 
hypobromous, 78 
hypochloric, 76 
hypochlorous, 78 
hypogai'c, 280 
hyponitric, 100 
hyponitrous, 102 
hypophosphorous, 112 
hyposulphuric, 92 
hyposulphurous, 92 
iodic, 81 
isethionic, 231 
isobutyric, 190 
isophthalic, 328 
itaconic, 291 
lactic, 247 
laevotartarie, 290 
lauric, 192 
laurostearic, 192 
leucic, 215 
linoleic, 281 
lithic, 268 
maleic, 277 
malic, 276 
inalonic, 252 
mannitic, 298 
margaric, 193 
meconic, 350, 353 
melassic, 300 
melissic, 193 
mellibic, 330 
mellophanic, 330 
mesitylenic, 329 
metaboric, 140 
metantimonie, 135 
metantimonous, 135 
metaphosphoric, 114 
metarseuic, 122 



Acid, metastannic, 391 
methylcrotonic, 226 
monochloracetic, 187 
morintarmic, 345 
mucic, 298 
muriatic, 72 
mj'ristic, 192 
nitric, 102 
nitrobenzoic, 327 
nitrosonitric, 104 
nitrous, 102 
nonylic, 192 
Nordhausen, 92 
octylic, 192 
oenanthylic, 192 
oleic, 226 

orthoantimonic, 135 
orthoarsenic, 121 
orthoboric, 140 
orthophosphoric, 113 
osmic, 373 
oxalic, 250 
oxalovinic, 198 
oxaluric, 272 
oxamic, 274 
oxybenzoic, 329 
palmitic, 193 
parabanic, 271 
paralactic, 248 
paramucic, 298 
pelargonic, 192 
pentathionic, 93 
perbromic, 78 
perchloric, 76 
periodic, 81 
phenic, 320 
phenylsulphurous, 316 
phocenic, 191 
phosphomolybdic, 347 
phosphoric, 113 
phosphorous, 112 
phosphotungstic, 373 
phosphovinic, 195 
phthalic, 328 
picric, 321 
pimelic, 253 
pivalic, 191 
plumbic, 386 
pneumic, 230 
prehnitic, 330 
propionic, 189 
propylacetic, 191 
protocatechuic, 345 
prussic, 339 
pyroantimonic, 135 
pyroarsenic, 122 
pyrobismuthic, 389 
pyroboric, 140 
pyroo-allic, 325 
pyroligrieous, 185 
pyromellitic, 330 
pyromucic, 298 
pyrophosphoric, 113 
pyrosulphuric, 92 
pyrotartaric, 291 
pyruvic, 291 



INDEX. 



433 



Acid, quinic, 353 

quinotannic, 345 

quinovic, 353 

racemic, 290 

rocellic, 254 

rosolic, 321 

saccharic, 298 

salicylous, 331 

salicylic, 329 

santonic, 344 

sarcolactic, 247 

sebacic, 254 

silicotungstic, 373 

stannic, 391 

stearic, 193 

suberic, 253, 281 

succinic, 253 

sulphanilic, 333 

sulphobenzoic, 327 

sulpbocarbonic, 245 

sulphocyanic, 341 

sulphoglucic, 300 

sulphovinic, 196 

sulphuric, 88 

sulphurous, 86 

sulphydric, 84 

tannic, 344 

tartaric, 290 

tartralic, 291 

taurocarbamic, 230 

fcaurocholic, 211 

terephthalic, 328 

tetraboric, 140 

tetrathionic, 93 

trichloracetic, 187 

trichromic, 375 

trimellitic, 329 

trimesitic, 329 

trinitrophenic, 321 

trithionic, 93 

ulmic, 300 

uric, 268 

urous, 272 

valerianic, 190 
Acids, 17, 154 

amido, 156, 208 

biHary, 210 

fatty, 183 

monobasic, 153, 183 

valerianic, 190 
Aconitine, 360 
Acrolein, 224 
Action of acetic acid, 188 

of alcohol, 172 

of ammonia, 411 

of antimony, 137 

of arsenic, 124 

of barium, 415 

of bismuth, 390 

of bromine, 77 

of carbon dioxide, 240, 244 

of carbon monoxide, 235 

of chloral, 202 

of chloroform, 165 

of chromium, 376 

of copper, 422 
28 



Action of hydrochloric acid, 75 

of hydrocyanic acid, 340 

of hydrogen sulphide, 85 

of iodine, 79 

of lead, 387 

of mercury, 428 

of nitric acid, 104 

of nitrogen monoxide, 99 

of nitrogen tetroxide, 101 

of oxalic acid, 251 

of phosphoric acids, 115 

of phosphorus, 108 

of potassium, 406 

of silver, 408 

of sodium, 406 

of sulphur dioxide, 87 

of sulphuric acid, 91 

of zinc, 419 
Addition, 149 
After-damp, 158 
Air, 95 

ammonia in, 97 

confined, 237 

solids in, 97 

water in, 96 
Alanine, 214 
Albumin, acid, 366 

alkali, 365 

egg, 362 

in urine, 362 

serum, 362 

vegetable, 363 
Albuminates, 365 
Albuminoids, 360 
Albuminose, 366 
Alcohol, 169 

absolute, 172 

allylic, 221 

benzoic 318. .23 

camphyl, 296 

cerylic, 180 

cetylic, 180 

cholesteric, 335 

cinnamic, 334 

ethylic, 169 

isopropylic, 178 

mannitic, 298 

mellissic, 180 

menthylic, 297 

methylic, 168 

myricic, 180 

propylic, 178 

styrolic, 334 

vinic, 169 
Alcoholic radicals, 149 
Alcohols, 150 

amylic, 152, 179 

aromatic, 323 

butyric, 178 

diatomic, 150, 230 

monoatomic, 150, 167 

pentatomic, 292 

primary, 151 

secondary, 151 

tertiary, 151 

tetratomic, 289 



434 



INDEX. 



Alcohols, triatonaic, 150, 274 
Aldehyde, 171 

acetic, 200 

anisic, 331 

benzoic, 330 

campholic, 296 

caprylic, 203 

cinnamic, 336 

cuminic, 331 

salicylic, 331 
Aldehydes, 154, 200 
Aldol, 225 
Ale, 175 

Algaroth, powder of, 135 
Alizarin, 338 
Alkaline metals, 393 
Alkaloids, 346 

cinchona, 353 

detection of, 348 

fixed, 350 

opium, 350 

strychnos, 356 

volatile, 349 
Alkarsin, 219 
Alantoi'n, 272 
Allotropy, 30 
Alloxan, 272 
Allyl, 221 

hydrate, 221 

iodide, 221 

oxide, 222 

sulphide, 222 

sulphocyanate, 222 
Allylene, 288 
Allylic series, 220 
Alphenols, 324 
Alumina, 382 
Aluminates, 382 
Aluminium, 381 

acetate, 384 

chloride, 382 

hydrate, 382 

oxide, 382 

salts, 382 
Alums, 383 
Amanitine, 207 
Amides, 156 
Ami do acids, 156 

benzol, 332 
Amines, 155, 332 
Ammonia, 98 

Ammonias, compound, 155 
Ammonium, 408 

acetate, 410 

bromide, 409 

carbonates, 410 

chloride, 409 

compounds, 408 

hydrate, 409 

iodide, 410 

nitrate, 410 

oxide, 409 

purpurate, 269 

salts, 410 

sulphates, 410 

sulphides, 409 



Ammonium, urates, 269 
Amorphism, 28 
Amygdalin, 342 
Amyl acetate, 199 

chloride, 162 

nitrate, 198 

nitrite, 199 

sulphates, 199 
Amylene, 229 
Amyloid, 367 
Amyloses, 299, 310 
Amy him, 310 
Analytical characters of alkaloids, 347 

of aluminium, 384 

of ammonium, 410 

of antimony, 132, 138 

of arsenic, 127 

of barium, 415 

of bismuth, 390 

of bromides, 81 

of calcium, 415 

of chlorides, 74, 81 

of chromium, 375 

of cobalt, 419 

of copper, 422 

of gold, 374 

of iodides, 81 

of iron, 381 

of lead, 387 

of lithium, 393 

of magnesium, 417 

of manganese, 376 

of mercury, 427 

of nickel, 419 

of nitrates, 105 

of phosphates, 114 

of potassium, 406 

of silver, 408 

of sodium, 399 

of sulphates, 91 

of tin, 391 

of zinc, 419 
Anhydride, antimonic, 134 

antimonous, 133 

arsenic, 121 

arsenious, 118 

boric, 139 

carbonic, 236 

chromic, 375 

hypochlorous, 76 

molybdic, 373 

nitric, 101 

nitrous, 100 

phosphoric. 111 

phosphorous, 111 

plumbic, 385 

silicic, 372 

sulphuric, 87 

sulphurous, 86 

tungstic, 373 
Anhydrides, 23, 154 
Aniline, 332 
Anthracene, 337 
Anthracite, 142 
Antimony, 131 

black, 131, 136 



INDEX. 



435 



Antimony, butter of, 135 

cinnabar, 136 

crocus of, 136 

crude, 131 

glass of, 136 

intermediate oxide, 134 

liver of, 136 

pentachloride, 136 

pentasulphide, 137 

pentoxide, 134 

protochloride, 135 

regulus of, 131 

trichloride, 135 

trioxide, 133 

trisulphide, 136 

vermilion, 136 
Apiin, 342 
Apomorphine, 351 
Aqua ammoniae, 98, 409 

cblorinii, 71 

fortis, 102 

prima, 102 

regia, 74, 104 
Arabin, 315 
Arabinose, 315 
Arburin, 342 
Argol, 403 
Aromatic series, 315 
Arsenamine, 116 
Arsenia, 116 
Arsenic, 116, 125 

acids, 121 

disulphide, 122 

flour of, 118 

oxides, 118 

pentasulphide, 123 

pentoxide, 121 

sulphides, 122, 125 

tribromide, 124 

trichloride, 123 

trifluoride, 123 

triiodide, 124 

trioxide, 118, 125 

trisulphide, 123 

white, 118 
Arsenical greens, 125 
Arsines, 219 
Atom, 8, 10, 11 
Atomic heat, 13 

theory, 8 

weight, 11 
Atomicity, 15 
Atropine, 359 
Auric chloride, 374 
Aurin, 321 
Auripigmentum, 123 
Aurous chloride, 374 
Azote, 95 
Azulin, 321 

Baking-powders, 404 
Balsams, 297 
Barium, 415 

chloride, 415 

hydrate, 415 

oxides, 415 



Baryta, 415 

Bases, 18 

Basicity, 17 

Bassorin, 315 

Beer, 175 

Beeswax, 199 

Benzene, 315 

Benzine, 159 

Benzol, 315 

Benzoline, 160 

Benzyl hydrate, 323 

Benzyl hydride, 330 

Betaine, 207 

Beverages, alcoholic, 174 

Bile acids, 210 

physiology, 213 

pigments, 370 
Bilifuscin, 370 
Biliprasin, 370 
Bilirubin, 370 
Biliverdin, 370 
Bismuth, 388 

hydrates, 389 

nitrate, 389 

oxides, 389 

salts, 389 
Bismuthyl, 389 

carbonate, 390 

nitrate, 389 
Black flux, 403 
Bleaching-powder, 412 
Boiling-point, 6 
Bone, 413 

ash, 412 

black, 143 

phosphate, 412 
Borax, 398 
Borneene, 297 
Borneol, 296 
Boron, 139 

bromide, 140 

chloride, 140 

fluoride, 140 

oxide, 139 
Brandy, 178 
Bromal, 171, 202 
Bromine, 77 
Bromoform, 166 
Bromoiodoform, 167 
Brucine, 358 
Butalanine, 214 
Butter. 284 
Butyral, 203 
Butyrone, 204 



Cacodyle, 219 

Cadmium, 416 

Caesium, 393 

Caffeine, 355 

Calcium, 411 

carbonates, 414 
chloride, 411 
hydrate, 411 
oxalate, 415 
oxides, 411 



436 



INDEX. 



Calcium, phosphates, 412 

plumbite. 385 

salts, 412 

sulphate, 412 

urates, 269 
Calomel, 424 
Camphol, 296 
Camphor, 295 

Borneo, 296 

Japan, 295 

laurel, 295 

monobromo, 296 
Camphors, 295 
Camphrene, 296 
Caouchene, 294 
Caoutchouc, 294 
Carbamide, 257 
Carbimide, 256 
Carbinol, 168 
Carbohydrates, 299 
Carbon, 141 

compounds of, 145 

dioxide, 236 

disulphide, 246 

monoxide, 234 

perchloride, 167 

sesquichloride, 167 

tetrabromide, 166 

tetrachloride, 166, 229 

trichloride, 167 
Carbonyl, 234 

chloride, 235 
Carmine, 273 
Casein, gluten, 365 

milk, 364 

serum, 363, 365 
Catalysis, 181 
Cedrene, 334 
Cellulin, 314 
Cellulose, 314 
Cerasin, 315 
Cerebrin, 286 
Ceruse, 387 
Ceryl hydrate. 180 
Cetaceum, 199 
Cetene, 197 
Cetme, 199 
Cetyl hydrate, 180 

palmitate, 199 
Chalk, 414 
Charcoal, 143 

animal, 143 
Chemistry, 1 
China wax, 199 
Chitin, 342 
Cholin, 206 
Chloral, 171, 200 

alcoholate, 202 

hydrate, 202 
Chlorine, 70 

monoxide, 76 

peroxide, 76 

tetroxide, 76 

trioxide, 76 
Chlorocarbon, 166 
Chloroform, 164 



Chloroiodoform, 167 
Chloromethyl, 163 
Cholesterin, 335 
Chondrigen, 367 
Chondrin, 367 
Chromium, 375 

oxides, 375 

sulphates, 375 
Chrysene, 338 
Cicutine, 349 
Cider, 177 
Cinchonine. 355 
Cinnabar, 424 
Cinnamene, 334 
Cinnamol, 334 
Classification, 26 
Coagulated albumins, 366 
Coal, 142 
Cobalt, 419 
Cocaine, 360 
Codeine, 352 
Coke, 143 
Colchicine, 359 
Collagen, 367 
Collodion, 314 
Colocynthin, 342 
Colophony, 293 
Combustion, 36 
Composition, 1 
Compounds, 7 
Conglutin, 365 
Conhydrm, 349 
Conicine, 349 
Conii'ne, 349 
Constitution, 23, 147 
Convolvulin, 343 
Copper, 420 

chlorides. 420 

oxides, 420 

salts, 421 
Corallin, 321 
Corrosives, 75 
Corrosive sublimate, 425 
Cosmoline, 161 
Creasol, 322 
Creasote, 322 
Creatine, 217 
Creatinine, 217 
Cresol, 322 
Cresylol, 318, 322 
Cristallin, 332 
Crith, 34 
Crocin, 342 
Crotonol, 280 
Crotonylene, 288 
Crystallization, 28 
Cumene, 318 
Cupric chloride, 421 

oxide, 420 

sulphate, 421 

sulphide, 420 
Cuprous chloride, 420 

oxide, 420 

sulphide, 420 
Curare, 359 
Curarine, 359 



INDEX. 



43 



Cyanogen, 338 
Cymene, 296, 318 
Cymol, 318 



Dahlinin, 314 
Daturine, 359 
Decomposition, 18 
Deliquescence, 40 
Deoxidation, 34 
Dextrin, 170, 311, 313 
Dextrogyrous, 32 
Dextrose, 299 
Diallyl, 221 
Diamines, 255 
Diamond, 141 
Diastase, 170, 299 
Dibromomethyl bromide, 106 

iodide, 167 
Dichloreihyl chloride, 167 
Dichloromethane, 163 
Dichl or methyl chloride, 164 

iodide, 167 
Dicyanogen, 338 
Diethylamine, 206 
Diethylia, 206 
Digitaiein, 343 
Digitalin, 342 
Digitaliretin, 343 
Digitalose, 343 
Dimethyl amine, 206 

benzene, 318 

carbinol, 178 
Dimethylia, 206 
Dimorphism, 30 
Diiodomethyl iodide, 166 
Disocryl, 224 
Divisibility, 6 
Duboisine, 359 
Dulcite, 298 
Dulcose, 298 
Dutch liquid, 229, 230 
Dynamite, 279 
Dyslysin, 212 



Efflorescence, 38 

Elastin, 367 

Elayl, 229 

Eleoptenes, 295 

Electro-negative, 18 

Electro-positive, 18 

Elements, 7, 12 

Emetine, 355 

Emulsion, 342 

Equations, 16 

Equivalents, 9 

Erythrine, 289 

Erythrite, 289 

Eserine, 359 

Essence of bitter almonds, 319 

of chamomile, 226 

of mirbane, 319 
Essences, 198, 292 
Etching, 69 
Ethal, 180, 199 



Ethene, 229, 287 

chlorhydrate, 230 

chlorhydrin, 230 

chloride, 229, 230 

glycol, 231 

oxide, 231 
Ether, 181 

acetic, 197 

amyl nitrous, 199 

ethylic, 181 

formic, 197 

hydrobromic, 162 

hydrochloric, 162 

hydriodic, 162 

methylic, 180 

muriatic, 162 

nitric, 194 

nitrous, 195 

oxalic, 198 

phosphoric, 195 

pyroacetic, 204 

sulphuric, 181 
Etherification, 181 
Etherine, 197 
Etherol, 197 
Ethers, 152 

compound, 153, 194 

haloid, 150 

mixed, 153, 183 

simple, 152, 180 
Ethyl, 149 

acetate, 197 

borates, 195 

bromide, 162 

carbinol, 178 

carbonates, 198 

chloride, 162 

formiate, 197 

hydrate, 169 

iodide. 162 

nitrate, 194 

nitrite, 195 

oxalates, 198 

oxide, 181 

sulphates, 196 

sulphide, 218 

sulphydrate, 218 
Efchylamine, 206 
Ethylene, 229 

alcohol, 231 

bichloride, 230 

glycol, 231 

hydrate, 231 

oxide, 231 
Ethylia, 206 
Eucalin, 306 
Eucalyptene, 297 
Eucalyptol, 297 



Fats, 279, 283 

phosphorized, 286 
Fermentation, 170 
Ferments, animal, 368 
Ferric acetates, 380 

bromide, 379 



438 



INDEX. 



Ferric, chloride, 379 

ferrocyanide, 380 

hydrates, 126, 378 

iodide, 379 

nitrates, 379 

oxide, 378 

phosphate, 380 

pyrophosphate, 380 

sulphates, 379 

sulphide, 378 
Ferrous acetate, 380 

bromide, 379 

carbonate, 380 

chloride, 378 

ferricyanide, 381 

iodide, 379 

lactate, 380 

nitrate, 379 

oxalate, 380 

oxide, 378 

sulphate, 379 

sulphide, 378 

tartrate, 380 
Fibrin, 366 
Fibrinogen, 363 
Fibrinoplastic matter, 363 
Fire-damp, 157 
Fluids, 5 
Fluorene, 337 
Fluorine, 69 
Fluviale, 295 
Foods, vegetable, 312 
Formamide, 208 
Formulae, 16 

empirical, 16 

general, 147 

graphic, 23 

of constitution, 23 

typical, 22 
Formyl bromide, 166 

chloride, 164 

iodide, 166 
Fraxine, 298 
Fuchsine, 333 
Furfurol, 298 
Fusel oil, 176 
Fusing-point, 6 



GADININ, 283 

Gaduin, 283 
Galactose, 306 
Galena, 386 
Gallium, 381 
Gasoline, 160 
Gelatin, 367 

sugar of, 208 
Gin, 178 

Glauber's salt, 396 
Gliadin, 365 
Glonoin, 279 
Glucinium, 381 
Glucosan, 300 
Glucose, 170, 299 
Glucoses, 299 
Glucosides, 299, 342 



Glycerin, 274, 275 
ethers of, 277 

Glycin, 208 

Glycocol, 208 

Glycocols, 156 

Glycogen, 313 

Glycol, 231 
toluyl, 324 

Glycollide, 247 

Glycols, 230 

Glycyrrhizin, 343 

Glyoxyldiurea, 272 

Gold, 374 

Grape-sugar, 170, 299 

Graphite, 142 

Guanine, 273 

Guaranine, 355 

Gum, British, 313 

Gum resins, 297 

Gums, 315 

Gun-cotton, 314 

Gutta, 295 

percha, 295 

Gypsum, 412 



H^ematin, 370 

Haematoerystallin, 369 

Haemochromogen, 370 

Haemoglobin, 369 

Helenin, 214 

Homologous series, 146 

Hydrates, 18, 23 

Hydrobilirubin, 370 

Hydrocarbons, 149, 228 
first series, 157 
second series, 2(27 
third series, 287 
fourth series, 292 
fifth series, 315 
sixth series, 334 
seventh series, 336 
eighth series, 336 
ninth series, 337 
tenth s°ries, 337 
eleventh series, 337 
higher series, 338 
series of, 228 
non-saturated, 227 
saturated, 149, 157 

Hydrogen, 33 

antimonide, 132 

arsenides, 116, 125 

bromide, 77 

chloride, 72 

dioxide, 67 

fluoride, 69 

heavy carburetted, 229 

iodide, 80 

light carburetted, 157 

nitride, 98 

oxide, 37 

peroxide, 67 

phosphides, 110 

silicide, 372 

sulphide, 84 






INDEX. 



439 



Hydroquinone, 324 
Hygrometers, 96 
Hyoscyamine, 359 
Hypoxanthine, 273 



Igasurine, 359 

Ilium mating- gas, 287 

Indican, 371 

Indiglucin, 371 

Indigogen, 371 

Indium, 381 

Inosite, 306 

Inulin, 305, 314 

Iodal, 203 

Iodine, 78 

Iodoform, 166 

Iridium, 392 

Iron, 378 

acetates, 380 
bromides, 379 
carbonate, 380 
chlorides, 378 
ferricyanide, 381 
ferrocyanide. 380 
hydrates, 378 
iodides, 379 
lactate, 380 
nitrates, 379 
oxides, 378 
phosphates, 379 
pyrophosphate, 380 
salts, 379 
sulphates, 379 
sulphides, 378 
tartrates, 380 

Isethionamide, 230 

Isodulcite, 343 

Isomerism, 147 

Isomorphism, 29 

Isoprene, 294 

Ivory black, 143 



Jalapin, 343 
James' powder, 134 
Javelle water, 401 
Jet, 142 



Kaolin, 383 
Kelp, 78 
Keratin, 367 
Kerosene, 160 
Ketone, 204 
Ketones, 154 
King's yellow, 123 
Kyanol, 332 



Lactine, 309 
Lactose, 309 
Lasvogyrous, 32 
Lcevulosan, 305 
Loevulose, 305 
Lamp-black, 143 



Lard, 284 
Latent heat, 6 
Laughing-gas, 99 
Laurene, 318 
Law of Ampere, 10 

Avogadro, 10 

definite proportions, 7 

Dulong and Petit, 13 

multiple proportions, 8 
Laws of Dalton, 7 

Gay Lussac, 9 
Lead, 384 

acetates, 387 

black, 142 

carbonate, 387 

chlorides, 386 

chromate, 387 

dioxide, 386 

glycocholate, 211 

iodide, 386 

monoxide, 386 

nitrate, 386 

oxides, 386 

peroxide, 386 

protoxide, 386 

puce oxide, 386 

red, 386 

salts, 386 

sulphates, 386 

sulphide, 386 
Lecithin, 286 
Lecithins, 206 
Legumin, 365 
Lethal, 199 
Leucine, 214 
Lichenin, 315 
Lignin, 314 
Lime, 411 

chloride of, 412 

water, 411 
Liqueurs, 178 
Litharge, 385 
Lithium, 393 

bromide, 393 

carbonate, 393 

chloride, 393 

hydrate, 393 

oxide, 393 

salts, 393 

urates, 269, 393 



Maclurin, 345 

Magenta, 333 

Magnesia, 416 
alba, 417 

Magnesium, 416 
carbonates, 417 
chloride, 416 
hydrate, 416 
oxide, 416 
phosphates, 416 
salts, 416 
silicates, 417 
sulphate, 416 

Malt, 170 



440 



INDEX. 



Maltose, 309 
Manganese, 376 

oxides, 376 

salts, 376 
Mannite, 298 
•Mannitose, 306 
Marsh-gas, 157 
Massicot, 385 
Mauvein, 334 
Meconine, 350 
Melampyrine, 298 
Melanin, 371 
Melezitose, 310 
Mellite, 330 
Melissin, 199 
Melitose, 309 
Menthol, 297 
Menyanthin, 314 
Mercaptan, 218 
Mercaptides, 218 
Mercuric chloride, 425 

cyanide, 426 

iodide, 426 

oxide, 424 

sulphide, 424 
Mercurcus chloride, 424 

iodide, 426 

oxide, 423 
Mercury, 423 

chlorides, 424 

iodides, 426 

oxides, 423 

salts, 427 

sulphides, 424 
Mesitylene, 318 
Mesoxalylurea, 272 
Metachloral, 200 
Metallocyanides, 341 
Metalloids, 26 
Metals, 26 
Metamerism, 147 
Methal, 199 
Methene, 229 

chloride, 163 
Methenyl bromide, 166 

chloride, 164 

iodide, 166 
Methyl benzene, 318 

bromide, 162 

carbinol, 169 

chloride, 162 

glycocol, 209 

hydrate, 168 

hydride, 157 

iodide, 162 

nitrate, 194 

nitrite, 194 

oxide, 180 
Methylamine, 205 
Methylene, 229 

bichloride, 163 
Methylia, 205 
Milk, 363 

of lime, 411 
Minium, 385 
Mixtures, 8 



Molecule, 7, 11 
Molybdenum, 373 
Monamides, 207 
Monamines, 155, 205 
Monochlormethyl chloride, 163 
Monochlorethyl chloride, 167 
Morphine, 351 
Mucin, 367 
Murexid, 269 
Muscarine, 207, 359 
Mycose, 310 
Myosin, 363 
Myricyl hydrate, 180 

Naphtha, 159 

wood, 168 
Naphthalene, 336 
Naphthydrene, 336 
Narceine, 352 
Narcotine, 352 
Nascent state, 35 
Neurine, 206, 286 
Nickel, 419 
Nicotine, 350 
Nitre, 401 
Nitro-benzene, 316, 319 

benzol, 319 

cellulose, 314 

glycerin, 278 
Nitrogen, 94 

bromide, 106 

chloride, 106 

dioxide, 100 

iodide, 106 

monoxide, 99 

pentoxide, 101 

peroxide, 100 

protoxide, 99 

tetroxide, 100 

trioxide, 100 
Nitrous fumes, 1 00 
Nomenclature, 20 

Oils, 279 

distilled, 294 

fixed, 279 

lubricating, 161 

volatile, 292, 294 
Olefiant gas, 229 
Olefines, 227 
Oleoresins, 297 
Optically active bodies, 32 
Orcein, 324 
Orcin, 289, 324 
Organic substances, 145 
Orpiment, 123 
Osmium, 373 
Oxalylurea. 271 
Oxamide, 274 
Oxycholine, 207 
Oxycinchonine, 355 
Oxygen, 35 
Oxyneurine, 207 
Oxyphenols, 324 
Ozone, 37 



INDEX. 



441 



Palladium, 392 

Pancreatin, 368 

Paraffin, 1(31 

Paraffines, 149, 158 

Paraglobulin, 363 

Paramorphine, 353 

Parapeptone, 366 

Parasaccharose, 310 

Paris green, 421 

Pearlash, 412 

Pentene, 229 

Peonin, 321 

Pepsin, 368 

Peptones, 366 

Permanent gases, 34 

Peruvin, 334 

Petroleum, 158 

Phenicin, 321 

Phenol, 320 

benzylic, 322 
cresylic, 322 
cyinylic, 323 

Phenols, 319 

Phenyl, 332 

hydrate, 315, 320 

Phenylamine, 332 

Phlorizin, 343 

Phloroglucin, 325 

Phosgene, 235 

Phosphamine, 110 

Phosphines, 219 

Phosphonia, 110 

Phosphorus, 106 
bromides, 115 
iodides, 115 
oxides, 111 
oxy chloride, 115 
pentachloride, 115 
pentoxide, 111 
sulphides, 115 
trichloride, 115 
trioxide, 111 

Phycite, 289 

Physostigmine, 359 

Picnometer, 4 

Pilocarpine, 360 

Pinite, 292 

Plasmine, 363 

Plaster-of-Paris, 412 

Platinic chloride, 392 

Platinum, 392 

Plumbago, 142 

Plumbates, 386 

Poisons, 75 

Polarimetry, 31 

Polymerism, 147 

Porcelain, 383 

Porter, 175 

Potash, 400, 402 

Potassa, 400 

Potassium, 399 
acetate, 402 
aluminate, 382 
arsenite, 125 
bichromate, 406 
bromide, 400 



Potassium, carbonates, 402 

chlorate, 401 

chloride, 400 

chromate, 402 

cyanide, 405 

dichromate, 402 

ferricyanide, 406 

ferrocyanide, 406 

hydrate, 400 

hypochlorite, 401 

iodide, 400 

nitrate, 401 

oxalates, 403 

oxides, 400 

permanganate, 402 

pyrosulphate, 402 

salts, 401 

sulphates, 401 

sulphides, 400 

sulphites, 402 

tartrates, 402 
Potato spirit, 179 
Proof spirit, 172 
Propiane, 204 
Propyl benzene, 318 

hydrate, 178 
Propylamine, 206 
Propylphycite, 289 
Protein bodies, 360 
Protein, 365 
Protogon, 286 
Prussian blue, 406 
Pseudoxanthine, 268 
Psychrometers, 96 
Ptoamines, 360 
Ptyalin, 368 
Pyrene, 338 
Pyrites, 378 
Pyrocatechin, 324 
Pyrodextrin. 311 
Pyrogallol, 325 
Pyroxam, 312 
Pyroxylin, 314 



Quercite, 292 

Quercitrin, 343 
Quick-lime, 411 
Quinine, 353 
Quinone, 324 
Quinova red, 345 
Quinovin, 343 



Radicals, 17, 146 
Ratafia, 331 
Realgar, 122 
Reduction. 34 
Resins, 297 
Resorcin, 324 
Rhigolene, 159 
Rhodium, 392 
Ricinine, 280 
Rock crystal, 372 

oil, 158 
Rosaniline, 386 



442 



INDEX. 



Rosin, 293 
Rubidium, 393 
Rum, 178 
Ruthenium, 392 



Saccharides, 308 
Saccharoses, 299, 307 
Saffranin, 334 
Sal ammoniac, 409 

volatile, 410 
Salaeratus, 403 
Salicin, 343 
Salicylol, 331 
Saligenin, 324, 344 
Salt, Epsom, 416 

of lemon, 403 

of tartar, 402 

Rochelle, 405 

Seidlitz, 416 

sorrel, 403 
Saltpetre, 401 

Chili, 396 
Santonin, 344 
Sarcine, 273 
Sarcosine, 209 
Scheele's green, 421 
Schweinfurth green, 421 
Sea salt, 394 
Secalin, 206 
Selenium, 93 
Septicine, 360 
Serin, 363 
Silex, 372 
Silicates, 372 
Silicic oxide, 372 
Silicichloroform, 372 
Silicon, 372 

chloride, 372 
Silver, 407 

bromide, 407 

chloride, 407 

cyanide, 408 

nitrate, 408 

oxides, 407 

salts, 408 
Soaps, 285 
Soda, 394, 398 
Sodium, 394 

acetate, 398 

aluminate, 382 

arsenite, 125 

borates, 398 

bromide, 395 

carbonates, 398 

chloride, 394 

glycocholate, 211 

hydrate, 394 

hypochlorite, 398 

hyposulphite, 397 

iodide, 396 

nitrate, 396 

oxides, 394 

permanganate, 398 

phosphates, 397 

salts, 396 



Sodium, silicates, 397 

sulphates, 396 

sulphovinate, 196 

tungstate, 373 

urates, 269 
Solanine, 344, 359 
Sorbin, 306 
Spermaceti, 199 
Spirits, 171, 177 

methylated, 169 

pyroxylic, 168 

wood, 168 
Stannic compounds, 391 
Stannous compounds, 391 
Starch, 310 
Stearoptenes, 295 
Steel, 378 
Stercobilin, 371 
Stethal, 199 
Stibines, 219 
Stilbene, 337 
Strontium, 411 
Strychnine, 356 
Styracin, 334 
Styrol, 334 
Styrolene, 334 
Styrone, 334 
Sucrates, 308 
Sugar, beet, 307 

candy, 307 

cane, 307 

diabetic, 299 

of gelatin, 208 

grape, 299 

inverted, 308 

of lead, 387 

liver, 299 

milk, 309 

muscle, 306 

physiology of, 300 

tests for, 302 

uncrystallizable, 305 
Sulphethylates, 218 
Sulphobenzide, 316 
Sulphur, 82 

bromides, 93 

chlorides, 93 

dioxide, 86 

iodides, 93 

trioxide, 87 
Sulphurea, 267 
Superphosphate, 396 
Supersaturation, 412 
Synanthrose. 310 
Syntonin, 366 



Tallow, 284 
Tannin, 344 
Tartar, 403 

emetic, 405 
Taurine, 211, 230 
Tellurium, 93 
Terebenthene, 292 
Terpine, 292, 297 
Terpinol, 297 



INDEX. 



443 



Terra alba, 412 
Test, Boettger's, 303 

Fehling's, 303 

fermentation, 303 

Frezenius' and von Babo's, 130 

Gallois', 306 

Marsh's, 117, 129, 132 

Moore's, 302 

Mulder-Neubauer's, 302 

Pettenkofer's, 212 

Piria's, 217 

Reinsch's, 127 

Scherer's, 216, 306 

Trommer's, 302 
Thebaine, 353 
Theine, 355 
Thialdine, 200 
Thymol, 323 
Tin, 390 

compounds, 391 
Tincal, 398 
Titanium, 390 
Toluene, 318 
Toluidine, 318 
Toluol, 318 
Trehalose, 310 
Tributyrin, 277 
Trichloraldehyde, 200 
Triethylamine, 206 
Triethylia, 206 
Trimargarin, 278 
Trimethyl benzene, 318 
Trimethylamine, 206 
Trimethylia, 206 
Trimorphism, 30 
Trinitro-glycerin, 278 
Trinitro-phenol, 321 
Triolein, 278 
Tripalmitin, 278 
Triple phosphate, 417 
Tristearin, 278 
Trivalerin, 278 
Trypsin, 369 
Tungsten, 373 
Tunicin, 314 
Turnbull's blue, 406 
Turpentine, 293 
Tutty, 418 
Typical elements, 27 
Tyrosine, 216 



Urea, 257 

determination of, 264 

nitrate, 259 

oxalate, 260 

tests for, 263 
Ureas, compound, 267 
Ureids, 271 
Urethan, 198 
Urinary pigments, 371 



Urinometer, 5 
Urobilin, 370 
Uroxanthin, 371 



Valence, 15 
Valeral, 203 
Valerine, 229 
Varech, 78 
Vaselin, 161 
Veratrine, 359 
Verdigris, 422 
Vermilion, 424 
Vinegar, 187 

wood, 168 
Vitelin, 363 
Vitriol, blue, 421 
green, 379 
oil of, 89 
white, 418 



Water, 37 

glass, 397 
hardness of, 49 
impurities of, 49 
mineral, 58 
oxygenated, 67 
purification of, 57 

Weight, absolute, 2 
apparent, 2 
atomic, 11 
molecular, 11, 14 
relative, 2 
specific, 2 

Whiskey, 178 

White lead, 387 

precipitate, 426 

Wine, 175 

oil of, 196 
spirits of, 169 

Wolfram, 373 

Wourara, 359 



Xanthic oxide, 272 
Xanthine, 272 
Xenols, 323 
Xylene, 318 
Xylenols, 323 
Xyloidin, 312 
Xylol, 318 



Yeast, 170 



Zinc, 418 

compounds of, 418 

ethyl, 219 
Zirconium, 390 



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